|In the past I've used these Nvidia downloads for 98:|
Although all versions I tried which specified they were for 98 worked OK the above were the only ones that didn't lockup when I used the 'shutdown windows and restart in msdos mode'.
That doesn't appear to be your problem but if you're going to try various versions you should probably try those.
As jam says, uninstall all prior attempts, including any drivers from your previous card and install when the only driver is the generic VGA. Check my # 3 here if you need to force generic VGA:
You're not really green until you're soylent green.