Need Help Reinstalling Windows 98 using F8

I need to know the steps to reinstalling win 98 and 2d. I know I shut down and at start up I press the F8 key, how dow I delete windows directory and how do I go to cabs Computer already had windows 98 and windows 2d on it. I was installing drivers for mediacom internet and got it loaded and working and then decided to add software. Not aware that 2d was already loaded I installed it again. Ever since I have had a Fatal exception error and it stated I have a 7308 error too. I need to delete my windows directory and reinstall windows but I am not sure how to do this. When the computer turns on I hold down my F8 key, then I see the command prompt screen with the safe mode options. But how do I delete the windows directory and load cabs? I need help as I need this computer for work on Tuesday