I've sought information on Avid Xpress here before but to no avail. For Avid system requirements, visit
http://www.avid.com, and find Avid Xpress on the the Products heading.
Try signing up for the forums at
http://www.videography.com. That's where more pros hang out.
With Xpress down to $695 MSRP now, I'm sure we'll be seeing more Avid users on this forum. Come back and enlighten us sometime! (I'm considering making the move to Avid Xpress in '04 when I build a dedicated video-editing PC.)
Good luck!