Just out of the blue today, my fan started working consistently and things got really slow, until I could no longer access task manager or the start button. I restarted the computer, only to come back to windows and find the same problem. The 2nd reboot, I managed to get the task manager up as soon as windows started, and noticed that svchost.exe was reading at 99%, and eating all my cpu usage. I closed it and came to post this problem on the website. I don't know if it's related but when I opened firefox it looked different at first (kinda more primitive??), and asked me if I want to have firefox as my default browser (I had done that ages ago).
Any ideas why? I'm going to run some scans now, see what comes up...