Vista stuck on loading screen

If there's nothing I can do and I reinstalling everything is the only thing possible....well....Please at least tell me how it happened so it doesn't happen again.
I don't know how it got this way, my mother was the one using it and according to her it shut down fine last night.
This morning when I turned it on, it won't go past the loading screen, with the bar just flashing by endlessly to no avail. I also tried getting in safe mode, and it would list all the drivers and what not that it was loading, and at one point just stop.
Once, a blue screen popped up, but it disappeared too quickly for me to figure out what it said, and it never came up again in the many times I kept trying to get it to work.
I also put in the installation CD and told it to start the computer that way, but after it gets past the screen where it loads all the files, it goes back to the loading screen with the bar near the bottom moving endlessly by.
I tried going with last working configuration (or something like that) and the same thing happens.
I'm currently running my live Ubuntu CD just so I could at least access the internet, and as you can see, this works just fine.
Some particulars: Dell Inspiron 1525, Intel Core Duo, Windows Vista...If you need any more information, please let me know.
I don't really know much about operating systems, if you have steps please explain it simply, without jargon and whatnot...
 
Hi Merlinnair, do you have any friends that have a good working knowledge with computers? There is a step I want to suggest but it will require a moderate familiarity with PC system hardware.
 
To take out your harddrive and slave into another system. From this system you should be able to do a) virus scans and b) harddrive diagnostics.
 
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