|It's likely your hard drive has died and that's why the bios is no longer detecting it|
OR, it that's not it, go into bios setup and make sure the IDE controrllers are enabled. Then see if you can have it detect the hard drive. Can't say for sure how to do that as each bios is a little different. You need to consult the manual for that.
If the bios isn't seeing the hard drive a bootdisk won't either. However, you should use a 98 bootdisk for all dos access since older dos versions may not be able to see the drive even if it is good. You can download a file that will create a bootdisk at bootdisk.com.
Real men don't use AntiVirus; they just reformat