The smaller partition is (from memory so almost certainly) Dell's
diagnostics. You can run these at bootup using F12. See eg Dell's
guidance for the Dimension 5000
http://support.dell.com/support/syst...m/adtshoot.htm

I agree the other partition will be for you to Restore the system to the
way it shipped. Not a good idea unless you want to spend many a happy
hour reinstalling software, service packs etc But worth keeping unless
you are desperate for disk space.
--
Robin
PM may be sent to rbw0{at}hotmail{dot}com