sounds like some of your memory spontaneously died. Not sure how much you know, but the system memory (also called RAM) is a fairly small stash of very 'fast' storage space that the computer uses to temporarily store a "process"-(a command; for instance, when you click on a program to start it) while it "waits in line", so to speak, for it's turn at using the CPU (central processing unit). This means, that without part of this memory, it's as if the "waiting line" has suddenly been shortened, but the amount of processes waiting is the same. To compensate for this, the computer allocates a piece of your hard disk (the big, but slow, piece of memory that everything in your computer is stored on) to use as RAM. But, as I said, the hard disk is slow. Very slow. The system memory is probably nearly ten, or more, times as fast. So, when part of the RAM died, it started using the hard disk (or even ignoring commands altogether), which caused extreme slowness.
So, now you need to fix it. First, this is not a serious problem. All you need to do, is buy a new RAM stick to replace the dead one. You will need to know what kind of memory it is (there are hundreds of types). So, I would advise taking the machine to someone nearby who fixes computers. They will be able to test my "bad memory theory" and tell you what type of memory to buy. They might even have an extra stick handy. The memory it's self shouldn't cost more than $40 in most cases.
I dont know much about computers, so ill try my best to be as detailed as possible.
I have a Windows XP home edition with intel celeron m.
Yesterday, my computer refused to shut down. all it showed me was "saving your settings" for about 3 hours.
I finally had to shut it down from the power button.
Today, I tried opening up Itunes, and it wouldnt open.
I tried going to the "Add or Remove Programs" and I got a blank list.
I tried going to "my computer" but it took soo long for it to search for my items.
Finally, I tried opening up my antivirus system, (Avast) it sort of just froze mid-startup.
Whenever I try to restart/shutdown my computer all I get is my blank desktop, no icons, task bar, just my background.