Activation issues from windows xp to 7

I had to format my HD and used my windows 7 upgrade disc (which I had purchased for my other pc) and installed it and all was well when I went to use my activation code and it wouldn't work. I called MS and they messed around with it and updated it when it locked up. I called them back and they said I had to buy a new copy of 7 and I disagreed. ISSUE IS: I tried all the youtube videos to go into cmd and delete slui after making changes and all looked good then in device mgr it said I had 3 days left so I thought I was screwed then today (3 days) it rolled over to 27 days left to activation. Is this going to keep rolling over and my problems are over or do I still need to cry to MS and try to get an activation code. I still have the slui file in the recycle bin so I can restore it when I need to use a code.

I will try it. I had installed it on my other pc and all is well but they wont let me install it on my 2nd pc's hard drive freshly formatted. Whats odd is the 3 day activation rolled over to 27 days rather then locking up the pc until I paid for a code. Maybe the cmd changes I tried just keeps the pc thinking it needs to be activated but wont lock it out?

No luck.. Tried

Hummm.. Interesting..I need both computers. When I got it I was able to use it a few times when I had issues on my computers. If a fresh format is done can the operating system or windows find out that its another hard drive? Still cant figure out why the activation went from 0 days left this morning to 27 days left an hour after it said 0 days. Odd

Just had an update now its back to 3 days left for activation..This is odd