Computer wont shut down / my computer wont open

Most computer problems I can solve myself but now I am at a loss. I can't even figure out if this is a hardware or software problem. Basically the computer starts up and works normally. But on shutdown it just stays on the logging off screen permanently.
Another problem I have is that when I double click on my computer, it just doesn't display anything - just the green loading bar.
Flash sometimes crashes in both firefox and iexplore.
Spybot service runs but i cant access the programme.
If I go to 'run' and type h: run hangs and I can't terminate the process with the task manager.
I did a full virus scan with Avast and found nothing.
Updated graphics card drivers
Cant seem to do an error check on my C drive.
Did manage to get the computer shut down from safe mode (once)
Can't seem to be able to burn CDs/DVDs
Apart from these problems, everything works fine: can access all data on harddrive, nothing else causes the computer to crash, things dont seem to run any slower than normal.

What should I do: format and reinstall of windows? What do you think is the cause of the problem?
I am running a compaq laptop CQ60, upgraded from vista a couple of months ago.

Thanks for your help

This website is not affiliated, owned, or endorsed by Microsoft Corporation. It is a member of the Microsoft Partner Program.