Solaris

power off, disconnect monitor and keyboard, attach a terminal (9600,n,8,1) to the first serial port, power up.

thanks, i appreciate it.... problem is is that im a very very new user and dont know exactly what that kind of terminal is... im trying to learn unix and i basically just found this thing and now im trying to get it to work.... an absolute newbie that really wants to learn... i've done quite a bit of reading (including on sun's site) but i wouldnt know where to get a terminal......any suggestions would be really appreciated!!!!!!!

It sounds like an HDD or memory failure. Memory would typically be indicated by some sort of message. It could be the HDD controller has failed so the disk spins but no data can be retrieved..... definitely check what a serial connection shows... hope that helps

how do i do that? do i have to find a monitor that has a serial connector (one that looks like a serial keyboard connector) and plug that in?

to throw another reason into the bag it can even be overheating due to a fan gave up working

... going by not so good memory here...

There is a chip that looks like a black caterpillar in the motherboard that powers the OBP, which has a battery (I believe is the CMOS?, don't remember). When this battery starts dying, sometimes you'll be able to boot (if you leave the system off for a while) sometimes you won't. You'd need to replace it.
If this is the problem, you will get a message in the console that would say somethiing about the motherboard time not being correct...