You should STRONGLY consider upgrading to XP. MS will NOT be offering support for WIN 98 at the end of this month.
If you can't, then try reformatting. However, as best that I can remember, you go into device mgr. to update the vid drvr.
Download the new driver for the card and REMEMBER where you put it! Then uninstall the current driver thru Device mgr. and restart.
Then back to DM and open "display adapters". Right click on the card listed and choose " update driver." Then choose "will specify location of....." then "browse" Enter the location of the setup files for the new driver in the command window. Hit next, and installation should start .
It's been a long time, but I think this is how I accomplished this.
You could also do a search and enter the question you want an answer to. I'm sure you'll find the proper method.