Say you've bought a legit copy of Windows 7, but you don't want to enter that activation code. A common situation! Well, there's a simple trick for extending that free limbo period for four months.All you've got to do is enter "slmgr -rearm" into the command prompt at the end of every 30 day period, and you're set. You can do it three times, extending the whole deal to 120 days. The same trick worked on Vista, and it's nice to see Microsoft allowing the little trick to keep working on 7. You know, for those of us who hate entering activation codes. [Telegraph via Engadget]