I suggest you read this:
http://www.tomshardware.com/howto/20...achine-01.html
since you will pretty much have to build a new system, your old dell system wont do into a new case as dell is very propritary, and you wont be able to use your dell components except for the hard drive and CD rom, and your new system will probably use DDR ram, while the latest dells I have seen (mid-2002) were still using SDRAM, despite having P4 processors, I would dump the whole Idea of upgrading, and just buy a new PC. dell is diffrent, so recylcling parts is much harder, if you want to attempt to mod your old dell case to fit this new mobo, go ahead and try, but it will be very hard.