i have 3 comps in my house running windows xp home, two of them seem to have compatibility issues with certain programs, but the third doesnt. they all have the latest xp service packs. here are some examples of errors keep occuring:

on my computer i try to run an old vb prog and get an error that says: "cannot find vbrun.dll", then another error that says: "windows cannot run this because its a 16 bit program". but it works fine on my other comp... why is that

on my brother's comp, he tries to play an older game called "ultima IX" and sometimes it has a "c++ runtime error" message. this has never happened on either of the other two comps.

anybody know what could be causing these erros and why they dont happen on all of the systems. all of these progs used to run fine on windows Me before we upgraded to xp.