[Blindmath] Recommendation: Laptop vs. Desktop

[Billy Baer]

Hello,
 
I need to purchase a new system because I am unable to download ChattyInfty
on my present system. There is some incompatibility that neither the vendor
or a computer consultant has been able to diagnose. The solution seems to be
a new system as my present one is old. 
 
I'm open to input about the pro's and con's of a laptop vs. desktop. 
 
I use JAWS, an audible graphing calculator and will be using ChattyInfty.  I
also use the usual Microsoft Office Suite.
 
Does anyone have any recommendations for specifications (memory, etc.)? I'm
intending to avoid Windows Vista and stick with XP.  Also, is there an
off-the-shelf model that would suffice or do folks find that having a system
custom configured works best. 
 
Thanks very much.
 
Bill Baer