boot to alternate drive in X.5.8

That's it pretty much. I'm getting spinning beach balls when I shouldn't. Tried booting w/C held down and it didn't work. Just prior to that on first boot of the day there was a long delay then I got a circle/w a line thru it where the apple should be. There is 4 gig and change in the memory slots. I did all I can do in disc utility till I can boot to another drive. I know I can use the disc and have one but still want to know how to reboot to an alt. drive. There is 599 gig of free space on the boot drive. Thanks,

Ron

Well it does help enormously if you provide model details and operating system.

If you have system discs, boot from them and run Repair Disk and see the state of your hard drive. If OS X.7/8 use Recovery to do the same thing.

For most Mac models released in the last few years you can select another boot drive by holding down the Option key immediately after the startup chime. Hold the key down until the menu of drives appears.