Have you seen the minimum requirements for ArcGIS 10?
CPU Speed 2.2 GHz dual core or higher
128MB Video Ram
The laptop I’m typing this on, my only work machine, is a C2D 2.0 GHz. I don’t meet the minimum requirements for ArcGIS 10. And of course minimum requirements in software vendor parlance is a delicate balance between the software engineers, who would be horrified if you tried to run their software at the minimums, and the sales folks, who really want to say the software will run just dandy on a Speak ‘n Spell.