Boot Failure

I wasn't sure which forum to post this question in... if I need to start another one, please someone let me know. I've messed up a computer... don't know how, don't know exactly what to do to fix it. Last night, after a really loud and irritating noise, I shut the computer down and rebooted, hoping to get rid of the noise (loud ticking like noise)

As it was trying to start back up, it continued that noise for a few seconds, then I got the following message....

BOOT FAILURE
Please insert BOOT diskette into A:
Press any key to continue

So ok... I found the boot disk, inserted it, and pressed any key. It took me to a few steps which finally led me to a menu...
Install Operating System
Install CD Rom
Change boot settings.... etc.

I wasn't sure what to do there, but everything I've tried, I get another message saying that the command can't be found and to type the command. The example it gives is .... C:\WINDOWS\COMMAND.COM

Is there any help for my dumb luck at all? Anxious to hear from anyone with suggestions....

Thank you!

 

OK, first thing what O/S? 98, XP? Important to know. Second, when your computer boots up can you see it detecting a hard drive? Its in the very beginning where it checks for RAM also. It sounds like it cant find your hard drive or a boot sector on your hard drive. Let me know about the O/S and I can help you further. Youll need to use a boot disk to get to the command prompt and see if you can access the C: Drive at all.