diff sizes

[camaro]

How would I know that a certain motherboard would fit into a certain case? I have a Dell XPS 233 and want to get a Athlon 700 and a motherboard that fits inside my existing case. Will I have to change the power supply or anything else since it's a totally different chip? Any help would be greatly appreciated.

[welsh wizard]

go to http://support.dell.com/us/en find you system and then get info on mobo type, then you can find higher spec mobo in same form factor
WW