Windows 7 continually needing to re-authenticate?

I have a partition on my 15 inch Macbook Pro 2.53 GHz. I have Windows 7 installed in BootCamp. (And yes this is a legally owned, and licensed version of Windows 7 Home Premium) I use VMware fusion 3 to access the bootcamp partition from within OSX (Snow Leopard).

But about a month or two into using it this way, Genuine Advantage pops up and tells me the copy of Windows 7 I am running is not authentic. I then try to authenticate, and it won't let me. I finally have to call Microsoft and have them work through it with me over the phone, and they manually reauthenticate it from their end.

Then again, it works for a month or two, and then I have to do it all over again. What's up with this. Is there anyway to stop it from happening? I used to run XP this way all the time and it never did this. Is there some thing I can do to make this stop happening?

Please help, this is very frustrating and time consuming.

 

Yes I have changed the processor and RAM settings from time to time. Thank you both for the helpful insight.

So this means that if you are running Windows 7, you have to choose between a BootCamp installation, OR a Virtual Machine. BUt probably shouldn't do both? That's a bummer. My old XP install was really nice to be able to either or. Bu t I can understand why this would happen. Thanks for the insight.

If anyone else knows anything more, or can confirm what has been stated here, please let me know.

 

OK. SO will try the boo camp and VM method together without changing the memory settings, and see what happens. I will report back my findings.

If anyone else has any further insight, feel free to keep posting.