Is done by useing the FORM FACTOR..
Chances are DELL Support will not give you one piece of INFO on the parts..
So you need to find your Motherboard FORM FACTOR..I'm quessing BTX...
Check the Intel website for matches on your MODEL-type..
microATX motherboards have dimensions like 9.6 X 9.6....
while the ATX motherboard is about 12.5 X 9.6....
Then the mounting screws differ in the two also..
If my memory serves me correctly....
The ATX has 12-screws..
the microATX has nine-screws..
if you can not fathom FORM FACTOR...don't even try..
you will waste your money..and wreck the PC..maybe even catch on fire..
Why not purchase a new TOWER...get a metal TOWER..
go to the Intel website..
check out PC Power & Cooling for a Power Supply(don't buy a Tower that comes w/PSU)..
SEARCH KINGSTON RAM website for a price on RAM/memory prices are very high now-a-days..even $$1000.00 for RAM..
Pentium 4 Processors are still on sale at almost 1/2 Price..but they are being phased out..don't get caught at the end of the line..
the SAME w/Digital Sound Cards..
things are moving towards VISTA..
Hardware is now useing the MOLEX connector..
Not a real difficult turn of events..
I would definitely consider the Intel Core 2 DUO..
with Dual Channel RAM of 512MBs x 2=1-GB..1065MHz..
its a hairy operation to build a PC from scratch..
I built a Intel PC from a DELL Dimension 2350 Tower..
it was a month of research/about an hour of build time..
some more research(about 2-weeks)just to figure out the FRONT PANEL Power SW./I needed to re-assign the color coded wires to fit the NEW Intel MotherBoard..
then it was still another month before I actually started the thing and was on my DESKTOP..
Check---Double Check...check again..
I was a nervous wreck.