A reinstall does not automatically destroy what was there before. Whether anything is left comes down to three answers: which option was chosen, whether the partition was formatted, and whether the disk underneath is solid state or spinning. This page walks through all six versions, including the two where the honest answer is that nothing can be done.
A single drive is £300 + VAT, and finding out what survived costs nothing. On a reinstall that free diagnostic is the most useful thing anybody does, because it settles whether there is a job here at all before you spend a penny.
The word reinstall covers everything from an upgrade that kept your files in place to a factory reset that scrubbed the volume. What happened to your data depends entirely on which of these was chosen, and on whether the disk underneath spins or not.
The best case by a distance. Setup moved the previous Windows, Program Files and Users folders into a folder called Windows.old and built the new installation around them. If that folder is still there, your documents and desktop are inside it and you may not need anybody at all.
Choosing the drive and pressing format writes a fresh, empty file table over the old one. It does not erase the rest of the volume. On a spinning disk the previous content is largely still sitting in the clusters, waiting to be identified. On an SSD, considerably less so.
Applications go, personal files stay. Where people lose data with this option it is normally from a second user profile, from files kept outside the profile folders, or from a desktop belonging to an account that did not survive the reset. Often recoverable, sometimes not lost at all.
The profile and its contents are deleted. If the extra option to clean the drive fully was ticked, the reset also writes across the volume rather than just clearing the index, and that changes the answer from difficult to no. Most people do not remember which they clicked.
The genuinely good outcome. The old volume is usually intact and simply unlettered, hidden or unmounted rather than gone. This happens constantly on machines with a small system SSD and a larger second drive, and it is often solved without a recovery at all.
It is removed automatically after ten days, and instantly if Disk Cleanup or Storage Sense was asked to clear previous installations. That deletion is a normal deletion, so the content may well still be present in the free space, which makes it a recovery job rather than a copy-and-paste job.
When Windows setup runs over an existing installation instead of formatting, it does not throw the old system away. It moves it. At the root of the system drive you will find a folder called Windows.old, and inside it the previous Windows folder, Program Files, and Users. Your documents, desktop, pictures and downloads are under Users, in a folder with your old account name on it. Opening it sometimes needs you to confirm an administrator prompt, which is normal.
If that folder is present, this may not be a job for anybody. Copy what you need out of it onto a separate drive, today, and be done. What it is not is permanent: Windows deletes Windows.old automatically ten days after the installation, and Disk Cleanup or Storage Sense will remove it on request at any point before that. A great many of the calls about reinstalls are from people who found the folder, meant to deal with it at the weekend, and found it gone on the Monday.
A quick format writes a new, empty file system structure at the front of the volume and leaves everything else exactly where it is. That is what Windows setup performs when you format a partition during installation, and it is why a formatted partition on a hard disk is frequently a productive recovery: the old content is still in the clusters, it just has nothing pointing at it any more. A full format is a different animal, because modern Windows writes zeros across the entire volume while performing one. After a full format there is nothing left to find, and it would be dishonest to take a drive in to prove it.
This is the part of the conversation nobody enjoys. On a hard disk, deleted and formatted data physically remains until something writes over it. On an SSD it does not work that way. When the file system releases blocks, the drive is told they are no longer needed, and the controller erases them in the background so they are ready to be written to again. That housekeeping normally runs within minutes of the machine sitting idle. Once a block has been through it, reading it returns zeros, and there is no cleverness that reaches underneath because there is no longer any charge held in the cells.
So a laptop that was reset a fortnight ago and has been used since, with an SSD in it and the option to remove everything chosen, is in almost every case a dead end. The same goes for any reset where the fully clean the drive option was ticked, on any type of storage. Saying that on the phone costs a firm work it could otherwise bill for, which is precisely why it is worth saying.
Plenty of these are recoverable, and the ones that are share a pattern. A spinning hard disk rather than an SSD, since the content survives until overwritten. A machine that was reinstalled and then switched off or barely used, rather than run for a month afterwards. An installation that went onto a different disk or a different partition from the one holding the data. A multi-partition machine where the old D drive is intact and simply has no letter. And installs that failed halfway, leaving fragments of both the old and the new structures on the volume, which look catastrophic and are frequently fine.
Before assuming a recovery is needed, open Disk Management and look at what the machine actually has in it. On a two drive computer, a reinstall frequently leaves the second disk perfectly intact but without a letter, so nothing appears in Explorer and everybody concludes the data is gone. The giveaway is a volume shown at the right size, described as healthy, with no letter beside it. Right click, assign a letter, and the files are back. Nothing was lost at any point.
The same screen has a trap on it, so tread carefully. If the old volume shows as unallocated space rather than as a healthy volume, do not accept the offer to create a simple volume on it, and do not initialise the disk when Windows suggests it. Both write new structures over the very area that has to be read, and both turn a straightforward job into a much harder one. Assigning a letter to an existing volume is safe. Creating anything new is not. If the screen is not clearly one or the other, take a photograph of it and ring before you click anything.
Every hour that a freshly installed Windows runs, it writes: updates, drivers, restore points, indexes, browser caches, and cloud sync pulling documents down onto the very free space that holds your old ones. Installing more software to look for the lost files is the worst version of this, because the installer writes directly into the space being searched. Shut the machine down, take the drive out, and let a copy be made before anything else touches it.
Plenty of these machines were rebuilt by a shop, a colleague or a relative who is good with computers, and three questions to that person are worth more than anything a laboratory can guess at. Was the partition formatted during setup, or was Windows put on over the top. Was any copy taken beforehand, onto an external drive or a folder somewhere on the network, because a surprising number of technicians take one as a matter of habit and then forget to mention it. And was the original disk replaced rather than reused.
That last one is the answer everybody hopes for. Where a slow laptop was given a new SSD, the old drive is usually sitting in a drawer at the shop or in the box the new one came in, complete and untouched, and getting the files back from it is an ordinary single drive job at £300 + VAT rather than a hunt through free space. Ask for it before it gets wiped and sold on or recycled. If it comes back to you, do not put it into a machine and start it up to have a look, because a drive that boots is a drive that writes. Leave it as it is and let the copy be made first.
Any single hard drive or SSD, NVMe included, is £300 + VAT. Cards and pen drives are £250 + VAT, arrays and NAS units start at £500 + VAT. The diagnostic is free, closes two working days after arrival and is the point at which you find out whether anything survived at all, which on reinstall jobs is the most valuable thing it does. No fix, no fee all jobs except electronic and mechanical failures, chip level work, DVR and Forensic jobs, so a reinstall on a healthy drive carries the guarantee outright.
Send the bare drive rather than the computer; nothing is dismantled at this end and any repair shop will unbolt one in minutes. The bench is at Guildford Business Park, about 40 minutes from Bracknell on the A322 and the A3, with reception taking drop-offs during office hours and tracked post arriving next working day from Berkshire, Surrey and London. Machines reach us from the business parks off the A329M, from Wokingham, Crowthorne and Sandhurst, from Windsor and Ascot, and from people who rebuilt a laptop on a Sunday and realised on the Monday morning what had been on it.
A fresh Windows writes constantly, and every write lands on the space your old files are still sitting in.
Post is how almost every job here starts. A tracked, insured parcel is far gentler on a struggling drive than a car boot and a day of errands, and something handed to Royal Mail in Bracknell today is normally booked in at the Guildford bench tomorrow.
If the storage is still bolted into a laptop, a tower, an iMac, a server or a CCTV box, unbolt it. The bare drive is what the bench needs, and no machines are dismantled at this end. Any repair shop will pull one out in a few minutes if you would rather not. The exception, and it is a hard one, is storage soldered directly to the logic board — Apple Silicon Macs, a few very thin Windows laptops, most tablets. If it does not come out, there is nothing that can be posted.
↓ Print the shipping & booking-in form (PDF)
Write Guildford Data Recovery on the label. Driving it down from Bracknell is roughly 40 minutes on the A322 and the A3; posting it costs you an envelope and a day. Either way you get a call once it is booked in, and the free diagnostic closes two working days later.
Not sure what should go in the box? Ring 0800 689 0668 before you seal it, or work through the free online diagnostic and let it ask the questions.