Help with crashing imac

I've got a 17" imac intel - about two years old. It has recently starting crashing frequently. The machine originally came with os 9 but I upgraded to os x. I want to wipe the hard drive - thinking that will help - but I have a problem/question.

When I upgraded to os x I did so off my friends family account license. I do not own os x. I do however own three macbooks that all originally came with os x. Can I reboot my imac with one of my macbook start-up discs???

Never tried this before and think it needs to be done but I am open to suggestions.

BTW - I have a time capsule and already have a complete back up of my imac data.

Any thoughts????

Firstly check with Apple Docs for the latest firmware update for your iMac, as you did not supply model details. Then go out and purchase OS X as the discs that came with any other computer will not boot the iMac.

Your info doesn't add up.

No Intel Mac came with OS 9. They stopped shipping OS 9 on any machine in 2002.