A similar problem to what I had about three weeks ago.
In my case this was almost immediately after installing SP 2. After several reactivations via the internet, I was suddenly confronted with "activate immediately" but would not let me get onto the internet, so this required a phone call.
This happened for the next 3 days. In desperation I reformatted. Since then all has been well
I still have this problem ands hotfix 811632 does not solve it.
my second computer, an ibm thinkpad which I only use when travelling, has developed the same fault. I have not booted it since installing service pack 2 'til today. guess what, I cannot get into window (W XP Home) without activating windows.
since this machine can only access web over dial up I was realistally forced to reformat hard drive and reinstall op system and service pack2. this seems to have solved problem.
howevert, with desktop with many complex programs, I am loathe to reformat except if absolutely forced to.