In my experience with these type of errors that usually means that you Hard Drive has crashed and is now unusable so the only thing you can try is to try and format and reinstall but if this does not work then you will have to purchase a new Hard Drive and either install it yourself or have it installed at a local computer shop unless the system is still under warranty in this case I would contact Dell.

I would like to add something to this:

Before you try to reinstall windows or something else drastic, try this. Open your tower and look for some wires that look like this:

http://www.dacs-giken.co.jp/photo/IDE-50.jpg

You should have one of these wires going from the motherboard to the hard drive. Make sure it is plugged in on both ends. You might want to unplug the wire then plug it back in, just to make sure it's making good connection.

Also, check the power plug on the hard drive. The power plug should have two black wires, a red wire, and a yellow wire.

Sometimes, computer manufacturers can get in such a hurry that they don't get the wires plugged in all the way and all it takes is a solid bump can break the connection.

Note: None of this will make a difference if your hard drive is dead. If the hard drive is silent or makes a consistent clicking sound (like a watch), then you most likely have a dead hard drive.

Additionaly, dell systems come with a built in utility for checking your system hardware. It should be F12 or something of the sort. Try running that, call Dell Tech. Suppt. and give them the error codes the utility shows. They will be able to tell you exactly what the problem is and what your options are.

I discovered why Alt F, Alt E, Alt B solves the "Primary Drive 1 Not Found" problem. It resets the BIOS to the default. However, what is really wrong is that the Secondary or Slave (HardDrive 1) is set to NONE in the BIOS when it should be set to OFF!!