How miserable is that Windows Vista gives you only one month of trial for a Operating system? I know it for registry cleaner or antivirus software. But for an OS, is not it too low? So here is a official way to raise it and forget about registering by pay.

1. confirm the activation expiry date with command: slmgr -xpr

2. Go to bottom left corner

3. Go to this path: HKLM\SOFTWARE \Microsoft\Windows NT\CurrentVersion\SL

4. Double-click SkipRearm and modify value to 1.

5. This registry hack does not have any sense on a system which has previously been activated.

6. Now keep in mind that to run thirty day extension command: slmgr -rearm

7. Restart PC. After it restarts, run slmgr -xpr and test expiry date.

8. Test registry setting SkipRearm, slmgr resets value to zero.