Got a major PIA problem with windows 2000. Currently doing a fresh install from the ground up, but I've got to the point after installing SP4 and the latest critical updates, that whenever I try to execute a setup program for anything (such as printer drive toolkit etc) I get the error :

Setup.exe attempt to access invalid address.

Can't find anything on the web about this, anyone have any ideas? I also had converted a slave HDD to NTFS just before the problems started if that's important.

Currently trying another fresh install to see if that cures it.

Bad ram?

That causes lots of strange problems, and the OS installer seems to be very sensitive about this.
Microsoft released a free and pretty good memory tester (iso image) that detected memory errors other programs didn't find (like memtest x86).

(Yeah i know, recommending a microsoft product isn't something i do very often, but it's good, trust me on this one)

Edit: Since the ms website is a pain, here's the url:
http://oca.microsoft.com/en/windiag.asp

Don't think it is the RAM, the system has been running for a couple of years with no problems in this area, plus previous installs have been no problem.

During the re-install I downloaded as many fixes as possible onto my laptop for transferring onto the PC and one of them was listed as a fix for "After SP4 install, updates are not installed properly" or something like that. Seems to have sorted things out after a clean install-->SP4-->that fix.

Cheers for the advice though.