I have an Everex Impact GC 2500 and it says I need to reinstall windows xp but I dont have the disk or product key code from yrs ago. Part of my sticker on the side of the computer is torn so I cant see all of the numbers but I can see a serial number on another sticker,.

If your current copy of Windows is still working, search online for the free 'PRODUKEY' software.
Download it. Unzip it. Run it, and it will tell you the 25-character product-key that you used when you installed Windows. Write it down!

> don't have the disk

Some computers have an option at power-on time to boot to the "System Recovery" environment.
From that environment, you can reinstall Windows.

Some computers have a utility to use your CD/DVD writer to burn a set of "System Recovery" disks. Get up to 10 CD-writable disks, and run the utility.

Or, contact the manufacturer, and order a set of "System Recovery" disks.
Probably about $20, plus $20 for overnight-courier.