Avoid WinXP Re-activation
The time may come that you'll need to reinstall your Windows XP. It could happen. Maybe you'll add a new motherboard or hard drive. Maybe you'll get constant errors and problems that just won't go away. Or perhaps you're a neat freak who wants to rid yourself of clutter and start fresh with a clean operating system. If you do reinstall Windows XP, then you'll need to re-activate it too—that is, unless you keep this tip handy 
See, the first time you activated XP it created a file called "wpa.dbl" that lives in the WINDOWS\system32 folder. By creating a backup of this file on disk, you can simply put it back into the folder after reinstalling XP and avoid the whole re-activation hassle. Here's how...
Go to My Computer then select your Hard Drive (usually drive C). Go to the WINDOWS\system32 folder and scroll way down until you find the wpa.dbl file.
Right-click and choose "Send To" then either Floppy Drive (make sure you have a disk in) or CD-R/RW.
Now, when you reinstall Windows XP you'll come to the activation screen—decline to activate and let the install finish.
Restart your computer in Safe Mode (keep hitting F8 at start-up then when the Advanced Boot Options menu appears arrow down to Safe Mode).
Find your way back to the WINDOWS\system32 folder. It's a good idea to rename the wpa.dbl file you're replacing just in case you run into problems, so call it something like "wpa.nothing".
Get the backup disk and copy the old wpa.dbl file back to the WINDOWS\system32 folder and reboot.
There you go—XP is up and running again.
