XP home edition, my computer drives not showing?

I have a XP Home Edition, version 2002, service pack 3, Dell Dimension DIM 3000, 2.66 GHZ, 1.25 GB of Ram.

A drive, C drive 40 GB, D drive CD, 2 USB front, 2 USB back ( 1 used by brother scanner, copier, fax machine).

1 cable modem, 1 router, 1 VOIP phone modem.

Problem, If I click on " My Computer " non of the drives are showing. no A.C,D,E or USB's. The only thing that is showing is the " brother machine, name Document and shared Documents ".

If I plug in a flash drive in the USB, I hear a dong, but nothing is showing. I can upload a file to the flash drive using win-rar and it is there ( I checked that with a different computer), but I can not find the drive. I tried to find the drives using windows explorer, but it is not showing either.

The drives are working but I can not transfer or check files on the drives, since I can not see the drives or files on them.

How can I make the computer to show the drives if I click on " My Computer " like it used to be?

Can you give me a more detailed instruction( what tab to push) to do that, since I know some about cp's but I am not a expert.

Thank you for your help?