A couple of things I do when I get weird shit like that is press Ctrl+Alt+Del to get the task box & if there's any files I don't recognise I look them up on Google to see it they're viruses.
Another thing is to click START - RUN & in that box type "msconfig" (without the quotations), click the Startup tab & look through & see if there's any weird shit selected that may be causing it. Try deselecting some of the ones you don't need & rebooting as a process of elimination type thing.
Failing that...
I've had problems like that with a couple of computers & found out the best way to resolve it.
There's a site called Tech Guy like this one only the members & mods are computer techies.
Start a thread there describing the problem. Someone there will probably tell you to run HijackThis (a handy free little programme) & post the log & look through & tell you exactly what you need to do.
They've sorted me out a few times.
There's another place called Bleeping Computer that looks pretty much the same but I've never tried that one.
Good luck!
