well, quite frankly. IBM sucks and I would just go ahead and get 256 and see what happens. But in all seriousness, Dell, IBM Gateway, Compaq, they all do this. They try to make your computer un-compatable with any except if it is from the company (even though one of the strong points abut computers is something called backwards-compatability where you can still use a computer from 1986 if you wanted to for example.) Anyways, i digress, I've had to fix my cousin's and my sister's IBm computers recently and quite frankl, they are very bad and I really suggest just try to get some differnet computer for like 300@$ or even less. Since you seem to know how to build your own computer somewhat, try
www.newegg.com. that is a great website for buying all these great computers, they also sell PCs from HP and Sony (the Vaio) if you're not up for building your own computer (it is really easy though) and well, good luck, I rreally suggest u get a new computer though