iLemming with an Intel Question

Please don't laugh (too much).  I need to help upgrade my aunts computer and she won't have a Mac.  Doesn't want to learn a new anything.  Her present machine is 133MHZ, 16MB RAM (72 pin SIMM) no USB, running Win95.  She can't spend more than $200.00(US).  I haven't used an X86 since Windows 3.1 but I'm the IT.

Question:

What do we want to be looking for?
Thank you

win2k wins on the basis that one can get a (legal) win2k disk cheaper than a (legal) xp disk.

Also, win95 dislikes more than 128 ram... its the main reason i junked that computer so many years ago...so either >>8 got lucky, or i got a shitty motherboard. chances are its the latter. ;-)