what a coincidence I had EXACTLY the same problem.., i had to get a new mother board and processor???It worked, or maybe a complete reinstal might do it.
happened after a lot of 'P2P' sort of stuff
your first post and you have tuts you have downloaded????
did you log in with a differant name or address? I had a 'bill the dill' name once and THAT might have been the problem, two names. I never really found out what the actual problem was but thats how I fixed it.
hope to see you again
take it easy and life will be easy