This works in Windows Server 2003 R2, with SP2, not with SP3 and must work similar with Professional. This is so simple to do I can’t think it took me evermore to know how to do it.

1. Go to Start -> Run -> type “regedit” you want to create backup, by selecting export in menu

2. Go to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
WindowsNT\CurrentVersion\WPAEvents

3. Modify value of OOBETimer from what it is to:
FF D5 71 D6 8B 6A 8D 6F D5 33 93 FD

Go through next steps earlier than you do it. You want know what you are going to do, as if you take extra time value will reset and you should try again.

4. Right tick on WPAEvents folder and select “Permissions…”

5. Select “SYSTEM” group, and in the list below check each box under “Deny”. I wanted to check first box and it automatically checked the others.

6. Press OK, close regedit and finished, your windows is activated.