It's Windows Vista, and startup would be normal until after the desktop icons and background loads - I can move the mouse but once I click or double-click something it will freeze. Ctrl + Alt + Del will not bring up the screen for the Task Manager either. I end up with no choice but to manually turn it off by holding down the power button. I started up in Safe Mode a couple times before (including once today) and tried opening all the programs I normally use and everything worked perfectly, and the laptop didn't freeze. Even my wireless Microsoft mouse worked with no problems. Could my Microsoft mouse possibly be the cause? It is connected by USB, and I always plug it in after my laptop finishes starting up. It has worked fine for 2 years but lately it seems to be freezing my laptop, i.e., when I plug it in it will not connect, and when I try to use the laptop mouse to click on something, the laptop freezes. However, even when I do not connect my wireless mouse the laptop will sometimes freeze after startup. I am currently using the wireless mouse - the laptop did not freeze when I plugged it in after startup, but the mouse had trouble connecting and so I had to manually connect by pushing the 'Connect' buttons on the mouse and USB.
I also ran AVG (the newly updated 2012 version) last night and found 0 infections.
So my questions are what could be the problem and how can I fix it?