Activating windows copy withot a product key.

Just follow the steps:

Click on Start
Find and Click “Run”
Type regedit
Click the plus next to “HKEY_LOCAL_MACHINE”
Click the plus next to “SOFTWARE”
Click the plus next to “Microsoft”
Click the plus next to “Windows NT”
Click the plus next to “CurrentVersion”
Click “WPAEvents”
On the right panel, find “OOBETimer” then double click it.
Now, Delete all the Values by highlighting it, then delete it
Then type in this value without the quotation mark “FF D5 71 D6 8B 6A 8D 6F D5 33 93 FD”
Then after that click OK,
Then on the left panel right click WPAEvents, then click on permissions
Then click System or SYSTEM, then Deny Full Control, then Click OK.
Then Exit Registry Editor by Click the X or the red X on the Upper Right of the Title Bar or press ALT and F4 at the same time.
To Very that it works, go to start, then “activate windows”, or go to start, then all programs, then “activate windows”
If it says that Windows has been activated.

Originally from: how-to-activate-windows-xp-without-product-key