You could always unplug the PC, then pop out the CMOS battery and try rebooting. The CMOS battery is the flat silver round thing, just pop it out and put it back in.
If you can boot up the system after this I would suggest googling for the "unofficial" win98se service packs, alot of people still have valid win98 discs laying around and with the sp3 you can even run XP only software on your win98 PC. It is a great way to get more life out of old hardware.
Removing the battery: one should wait something like an hour before the Cmos Ram is erased. I've seen one keep its data for 20min without the battery, just on a supply filtering capacitor. Useful when you replace the battery as well.