Did both go away at the same time?
For the internal, restart, find whatever it says to do to enter startup (usually F2, Delete, or F10.) Check the basic setup. See if it recognizes it in the BIOS.
Start in safe mode. See if it recognizes at least the internal drive there. If so , my guess is a software issue or some such.
Past that, ask to move this query to the tech issues and bugs section, so the folks there can take a gander. 
I have asked everyone i know, no one can help...
I have a Dell XPS with Win XP.
I have an internal CDRW/DVD drive and an external one.
My computer is not recognizing these drives any longer... no clue when it started... didnt do anything recently to teh PC...
I have uninstalled them both and reinstalled... no help... tried to update drives... none available...
Any advice?
No one goes there anymore, it's too crowded...
"The potato goes in the FRONT."