Hmmm, hmmm. XP... ick. I'm not even gonna get started on that. You've already taken the plunge into the abyss, so there's only so much help anyone can offer. You have my condolences.
Anyway, putting that aside... first off - network location? If you're trying to run this program (or most programs, for that matter) off a network, then
don't. It's just a bad idea. Windows does a fair job of fooling programs into thinking that network drives are local, but it's not 100%.
If it's not on a network drive, then something obviously got very bent when you upgraded. What OS did you start out with (before upgrade)? Ordinarily, I would just keep messing around with it and try to fool it into thinking it's found what it wants. That network location thing though...
Honestly, my recommendation would be to just blow the whole system away and reload everything. OS upgrades are kind of a crapshoot. A clean install is a much better option. If you really want to do it the hard way though, then you're probably going to have to hack 3d studio out of the registry manually, delete the files, and do your reinstall.
This little program should be of some use. Also, just go after the main program entries. If you're re-installing anyway, it's not going to matter if a few file associations break, since they'll be reset in the re-install anyway.
Obviously, manually hacking stuff out of the registry is not a preferred way of doing things, but sometimes it's the only way to get things done.