you don't know how to provide more details or what you have tried or are you just lost?
What OS is on it? and this is a 4-drive 65 lb workstation and not a MacBook Pro notebook.
Lion or ML Recovery Mode
Resolving Kernal PanicsMac OS X Help
Isolating Issues in Mac OS
Get Help with your Product
Mac OS X & Mountain Lion Community
Startup Manager: How to select a startup volume
Troubleshooting: My computer won't turn on
And just in case....