1. If the computer has problems but can still enter Windows, click “Start → Programs → MS-DOS Mode” in order. You can also click “Start → Run” and type “command” in the dialog box that opens (without the quotation marks, same below). If your system is Windows XP/2000, then type “cmd”, and you can likewise enter DOS.
2. For Windows 98, you can also click “Start → Shut Down”, then in the dialog box that appears choose “Restart the computer in MS-DOS mode”, and you can enter DOS.
3. After startup passes the self-test, when the words “Starting Windows 98…” appear on the screen, immediately press the “F8” key, then choose “Safe Mode Command Prompt Only” or “Command Prompt Only”, and you can enter safe mode DOS or pure DOS.
4. If the system has crashed, restart the computer, hold down the Ctrl key, and in the screen information that appears choose “Safe Mode Command Prompt Only” or “Command Prompt Only”, and you can enter safe mode DOS or pure DOS.
5. If you cannot enter Windows, restart the computer, enter CMOS, change the first boot order in the BIOS (1st Boot Device) to the floppy drive (Floppy), save it, then insert the system disk.