As there is the slmgr -rearm command to extend your trial on Windows Vista and Windows 7, there is also a command to do the same on Windows XP. To use it, open a cmd window and enter: rundll32.exe syssetup,SetupOobeBnk
Extend Your Windows 7 Trial
If you have gotten yourself a Windows 7 trial of any edition and it is about to expire, but you need more time to use it for whatever reason, there is a cmd command that allows you to extend the