mac problem

[myrrh]

So, my friend calls me up and says his mac is dead. I take my laptop over so we have internet access and take a look at it.

It doesn't let you boot up in OS X and when you boot up in OS 9 the screen is all distorted looking. The basic stuff like reseting the RAM and going through restarting it were done.

In OS X, it tells you that you need to restart the computer, then after restarting it, it tells you that again, and basically enters into a loop.

In OS 9, you have some degree of doing things, but I suck at OS 9, since I have been only using my Mac since OS X.

I figured that it would be best to reformat it. It wouldn't let you boot off the OS X disk, but it did let you boot of the OS 9 disk. When it began to reformat it gave us this error:

macintosh HD could not be checked

It asked to continue without checking, or to cancel the install.

I checked online and didn't see anything that might be useful in explaining what this error is. Does anyone have any idea's or suggestions?