Sounds like hard disk has either failed or corrupted.

If you don't know much about two computers then you have two options

1) contact Dell and get them to help. Be warned they will not save any data that is revoverable. If under warranty then this ought to be your first option, except for possible problems about data recovery.

2) contact a local computer shop, not the big one starting with P.

Hope this helps

Yeah sounds like the hard disk is dead or windows is corrupted, either way your looking at a big problem. Return it to dell if possible or if not, then be prepared to shell out a laod of cash, and most likely lose all of your stuff.

How can I fix it myself?

To do it yourself, buy a new hard disk and reinstall windows on it from the windows CD but if you have an oldish Dell then you probably wont have a CD, you would have probably had a recovery partition which is most likely dead, as it was on the hard disk, meaning youll need to shell out a load of cash (probably more than the PC) to buy a new Operating System.

to get back your data supposedly putting your harddrive in the freezer helps...

Um, before you waste time and money, make sure that the hd is connected properly.. Many times, a loose connection can occur when moving the computer and such. Open the case, and make sure that both the IDE and power connectors are firmly in place (I'm assuming its IDE, it could be SATA).

If this does nothing.. check in your BIOS whether or not it even shows the hd.. I suggest contacting dell, then a data recovery business.. they have some high-tech mirroring machines and such that can work some magic, and recover almost anything. Next, they should determine whether the hd is still usable or not.. if not, buy another one.. and hope you still have the product key to your OS lying around.

do you know that the CIA can extract data by looking at the harddrive with a microscope?

A microscope? Says who? Thats impossible.. the data is inside the hd on the little rotating disks.

yeah they look at individual disks.