My computer froze in firefox and wont turn on now.

My Mac OS9 desktop computer froze in firefox yesterday but the mouse continued to work. I had to force the computer to shut down with the on off button because non of the keys or mouse clicks worked for shutting it down. I let It rest over night but today I went to turn it on but it won't go past the grey screen and grey apple as it goes to re boot. I never updated the software and am wondering if this is the problem. I heard so many disappointing encounters that I thought I was very happy with my operating system and didn't want to change. What should I do.