Press power button for longer than 5 secs.
not really trying to be pedantic here, but well, that press the power button for 5 seconds or more is an ACPI thing.
as the original poster is using pcmcia cards, on a win98 laptop, we can be almost 100% sure that it only supports APM, hence you would only need to push the power button for 1/20th of a sec and all power will be gone, all hail the button pusher
the laptop simply crashed, so remove all power (which includes the battery) and switch it on again.
the bright side to this sad story is that the original poster hasnt responded. there is a simple reason for this. he or she left the ac/dc unplugged and 5 minutes later the totally-shagged battery from last century gasped its last breath, and gave up the ghost. machine dead. and then they plugged the ac/dc back in and are merrily computing once again.
as an aside, unexpected pc card removal was a big problem, and most drivers managed to work around it, but NICs tended to still be problematic, so I can also (confidently) deduce the laptop was using a pcmcia nic, and has no onboard nic, which will aid in determing its age as being of the pre-acpi era.
Werner is the man as usual.