Printers disappeared

On a computer with Windows XP Professional installed, my printers frequently
seem to disappear. In the printerlist not a single printer is shown. In for
example Word, i can select all three of the installed printers and print on
them, but i can't change the setting of these printers (so i can't print in
landscape etc...). In outlook, I can't even print anything because i get the
message that there is a problem with my printers.

The first 2 times that it happened, the problem could be solved by restoring
the setting of a few days earlier. Now, I don't seem to be able to solve it
anymore. I already installed all the latest updates (under which also XP
SP2), but the problem remains.

The printers installed are : HP LaserJet 6P on LPT1:, CF-2002 Minolta copier
via network (IP-adress) and Dymo Labelwriter 330Turbo on Com1.

F1...F1...F1