just got this at start up for the first time...

windows activation error

a problem occurred when windows tried to activate. error code 0x80070426.
for a possible resolution, click 'more information'.
you can also contact microsoft by phone to help resolve this problem.

anyone heard of or dealt with this error??

okay, now it's suddenly telling me i don't have a genuine copy of windows vista and i've been using it since the middle of june. i purchased it from newegg.com with most of the rest of my parts. i can't even log on now...

I saw this with a simple search of your error code you posted. Have you tried to enter Safe Mode?

http://www.vistax64.com/vista-inst [...] 70426.html

http://www.microsoft.com/technet/s [...] &LCID=2057

i can't enter safe mode. when i try, the files start loading and it never finishes, just catches and stays there.

i no longer have a genuine copy of vista. i can't get to the registry, command prompt, disk scan etc. i don't think can i?

Call Microsoft at the number given. They will give you a new licence. Takes 5 minutes.