if your trying to clear the bios password the standard cmos clear using jumpers or the proceedure i explained above should work for any pc. just removing the cmos battery wont work you have to short the contacts. never fails.
if you're talking bout the windows admin password you need wininternals erd locksmith or PE with locksmith
by the way if you look around on the net you can find free downloads of tech manuals for your dell all quite legally and plenty of rescources that will give you good accurete info. try eserviceinfo.com