just at a quick glance, you have two resident AV services running - Norton and AVG. With this arrangement your pc is in dire straits - they conflict, and badly. Basically, they spend a lot of time checking each other's virus signatures. So if you can access one, say by desktop icon or tray icon, just stop one from running. Then decide which to remove, and uninstall it. I know which one I would ditch...
Come back with how you get on, cos otherwise your log looks clean.
boss, that log is clean; i have no good idea about what could have befallen you. It could be some damaged registry entries, but first i would suggest you try this - check for any damaged windows components [and automatically replace them..] by inserting your windows install CD and going start > run, and typing
-be prepared to press enter quite a few times..