The FMS logs will tell you exactly what is happening. You're saying that you can connect to the admin console? That's just one part of FMS, are the other parts fine after a restart?
iMac 2 meg RAM
I'm sure that is a typo, but even if it is 2GB, that is very marginal. FMS is know to not start properly if the hardware does not conform to the minimum requirements. Something to look into...