Having something of an interesting problem with my laptop at the moment.
Basically, after an hour of running, and I mean dead on an hour every time, clock speed snaps up to 100% and stays there until I power it down. Started a couple weeks ago, figured it was a virus of some description, but neither Symantec or Spybot found anything note worthy. Dropped it off at Luke's place to see if he could figure it out, couldn't replicate the problem, and it was left running over night and the next day. When I got it home, did it first time, disconnected my external HDD which we figured could be problem, still did it, took it to a friends place the next day for a Dexter marathon and it performed faultlessly.
Then when I got it home again, problems. Opened up Task Manager, and had a look around Resource Monitor, Internet Explorer, which I only ever used to download Firefox, and has been quite content to sit in the background ever since, is running up to 90% of available processing power, end process and everything returns to normal. But I basically have to do it every time it happens.
So my new problem is, uninstalling. How? It doesn't appear in Add/Remove, and I have a feeling just deleting the file won't quite cut it...