You can buy such media but the version you need varies. You might need Lenovo's version, or some XP Pro. For the Lenovo version hit their web site and hope they sell such.
For the full versions try newegg.com
As to keeping your files, that's all about backup. Hard disks fail all the time. We only lose what we don't backup.
I have a Lenovo T60 Laptop running Windows XP. I got this computer free (an old corporate computer), so it came with Photoshop and those sorts of things. I then got the "Unmountable Boot Volume" Blue Screen. I read about this on the internet, and found that you need the disks that came with the computer to fix it. I do not have these, but read there is a download on the Microsoft Site of these, yet I can't find it. I want to keep the programs and my files, so is there any non-reformatting fix to this? Safe mode also gives the same error. Help is needed!