Recovering data from HDD after reinstalling Windows?

[arrdnic]

Hello everyone,

Unfortunately I messed up.
My laptop (very old) was missing its operating system - it didn't boot up at all. So, I downloaded a new version of Windows XP onto a boot device and installed it onto the HDD of the laptop.
I remember accessing it many months ago and being shocked that the HDD's space was no longer occupied by all of my files.
Unfortunately, trying to regain access to the computer today, I seem to have forgotten the password for Windows XP.
I can load up a live version of GNU/Linux, but I'm here to ask:
Is it worth it? Will my data be recoverable, or not?
It just seems that people go through so much time and effort to completely wipe their hard drives with tools like Boot and Nuke, will that fresh installation have really completely wiped all of my data? If it is possible, how can I recover the data that I have lost?

Thanks so much for any help.

[EDIT] I don't know if this is good news - but I did not install anything else onto the computer after I installed Windows. I have not touched anything when I realized that my data might have been gone. I have not made any attempt to install another operating system recently. I am just left with a computer that had visible data - I installed Windows that made the data invisible, and now I don't have access to the operating system or the data.
Fingers crossed!

[strollin]

The fact that you installed an OS (or wrote anything to the disk) has made it more difficult to recover your files.  Some may not be able to be recovered at all but others might be.  You could try downloading a utility like Recuva and running it to attempt to recover your files.  Good luck.

[arrdnic]

Thanks a lot for the reply -  do you have any advice with regards to how I can use Recuva on my system - as I said, I don't know the password the the laptop anymore.
I don't want to reinstall a fresh version of Windows again in case it might destroy even more data. How should I proceed?

Thank you for your help!

[patio]

Laptop password or Windows password ? ?

[arrdnic]

Windows password - I know for a fact that it wasn't a standard dictionary word, by the way.
Also, none of the files are encrypted on the laptop - I forgot to mention.
The BIOS password is unset (thankfully).

[Mark.]

how was, and now is, the drive on the XP machine formatted?  NTFS vs FAT changes recovery chances.
did you delete the existing partition during the reinstall of XP?

but from a high level point of view, you've just written 20-30gigs worth of data to that drive, potentially overwriting the majority of your data..
not to mention killing the previous $MFT, so at the very least, all your data will be classed as 'lost' and you'll only be able to recover the first cluster of any file.

run Recuva with a Deep Scan, prepare for it to take many hours, and despite it showing file status of Excellent, try opening some recovered files, chances will be the files are corrupted and cannot be accessed.  but you have to try.

let me guess, you have no backups...

[Geek-9pm]

Arrdnic,
It would seem your problem began when you did not start backup plan.
Do no try an write  any thing to the drive.
Use another working PC o help you recover any data.
The laptop HDD can be place in an external enclosure with a USB interface..
Here is a list of free recovery software.
http://www.techradar.com/news/software/applications/best-free-data-recovery-tools-1321723
Piriform Recuva is top rated. Others might work differently.
DMDE Free Edition has some features taht might help.

Is any of the data valuable? Seagate offers data recovery for a price.
They also offer software if you want to do it yourself.
https://www.seagate.com/services-software/recover/