You could try removing PC-cillin 2007 and putting 2006 back in again.
Same thing happened to me back in 2002 when I was using Norton.
Norton 2002 was better than 2003. So every year till 2006, I just removed Norton 2002 when it was about to expire and reinstalled 2002 for another year. It worked great and got all the auto updates from Symantec.
Now I use Avast and like it better than Norton.
Norton can be tricky removing. You have to get a 'registry cleaner' (it's free at Download.com) to remove Norton and Symantec registry keys left behind when you uninstall, plus you have to do a search of 'files & folders' after removing Norton. They always leave junk behind on the normal uninstall to keep you from simply reinstalling the AV for another year free.
This trick worked for Norton.
I used Norton 2002 till 2006, maybe it may work on TrendMicro's PC-cillin.
