Hey. First of all thanks heaps for looking at my thread and i hope you are able to help me out. 
About 2 and a half hours ago i turned my Compaq Presario F500 Off.
Please note i am running windows vista home edition
I came back to it about an hour ago to find something strange happening.
First thing i realised something wasnt right was when i was loading the 'welcome screen". That in itself took 2-3minutes to be done and after that it said "preparing to load desktop". That took about another 2-3 minutes. So in total my startup took 6 minutes give or take a minute.
When it got off that screen I realised something was totally wrong. I am missing about 3/4 of all the icons/folders i had on my desktop, my background has changed, programs that i never had to open on startup have opened (Windows Sidebar + Synaptics Pointing Device), everything has changed. All my features that i had, settings its all gone. 
The most interesting thing is that when the desktop started to load a little bubble came up in the bottom right of the screen (taskbar) saying that "my user profile didnt load correctly". It goes on to say that if i am to change any settings it wont save it for next time i turn it on (So i will be back to missing 3/4 icons/folders etc etc)
Could i have a virus? I do scans regularly.  Could my laptop just be on its way out? 
The last thing i was doing when the laptop was working 'properly' was listening to Itunes.
All help/information is greatly appreciated. Thanks heaps :)