Was the drive making any odd noises? Clicking maybe or just loud?
This could indicate a bad drive.
Here are a few things you can try:
1) Get a copy of Knoppix - this is a bootable linux cd (you need to enable
the boot device in the bios to allow booting from cd). This will at the very
least tell you if you hard drive is working as it will show you the hard
drive on the desktop.
If the hard drive is not showing you could have a bad controller, bad cable
or bad drive.
2) If the OS still does not boot and you have data that you need you might
try removing the hard drive and seeing if you can place it into another
working computer as a slave drive and recover data this way. This will only
work if the hard drive has not fail.
3) Try placing a know good drive in your computer load the windows xp
operating system and see if it works - this would rule out the problems
above.
4) Check to see what kind of hard drive it is and search the net for that
particular hard drive manufacturer - they ususally have diagnostic tools that
will help you determine if the hard drive is not working. You could also down
load Ultimate Boot CD
http://www.ultimatebootcd.com/ you need a program that
can burn an ISO. Once again this is a bootable hard drive utility cd and has
most of the common hard drive manufactures on it.
5) Swap the IDE cable (that's usually a grey ribbon cable) connected to your
cd rom with your hard drive (remove the coloured power connector as well from
the cd-rom). Doing this may help you determine if the controller is bad.
Some of these steps require a working knowledge of computer hardware and
steps need to be taken to protect your computer and you. If you are not sure
seek someone who can help. Or take it into IT store and tell them what has
happened and anything else that may help them determine the best steps to
take.
Hope this helps