Windows 98 can be reinstalled fairly easily, go into the control panel, then add remove programs, then I believe there is a startup disk tab, click that, insert a blank floppy and click on create disk. This then creates the boot floppy. Insert floppy disk and power on, insert windows 98 cd-rom. It will ask if you want to start with or without cd-rom support, with cd-rom support is neccessary, it will leave you at an a: promt, simply change to cd-rom drive d: by default, type in cd win98 and press enter then type setup and proceed through setup. Or, if no floppy disks, enter bios on bootup, DEL key or F8



Then enter through to advanced cmos setup



And then change the boot sequence to cd-rom.

Apply changes and restart.

Windows ME can be done in a similar way, except the cd-rom is not bootable, so either boot off the windows 98 floppy and navigate again to the cd-rom drive, I think it's cd win me then type setup.

Windows 2000 / XP cd's are all bootable and setup runs automatically so just follow it through, my sticky at the top of this room may help.