you need there flash utility.
here is a link to 98 dos boot files, use this with teh HP flash utility on a USB drive and it will load dos. this allows you to run everything from spinrite, to mem86 to this update software http://files.extremeoverclocking.com/file.php?f=196
disreguard everything above that line, i misread thinking you were updating your cards firmware.
for driver you open device manager, go to the device, properties, update driver, select driver for this device, have disk, select the type of device you are updating on, then point the program to the directory of your driver. in this case it would be driver/amd64 and tell it to install. it may display many versions of your card in this driver so make sure you know teh exact model of your card before you select one on teh have disk screen. then your done.