Question : Problem: How do I tell if my hard drive has failed?

Powerbook turns on but small icon in the middle of the screen flips from a old mac icon to a question mark (?).  I booted from DiskWarrior but it didn't see any hard drives to fix.  Then booted from the OSX install disc but could select a disc to install operating system.  I'm pretty sure the hard drive is fried.  It was working fine last night.  I rebooted before going to bed and this morning the computer was hotter than I had ever felt it before.  Any suggestions?

Answer : Problem: How do I tell if my hard drive has failed?

I believe that the Question mark means that the Mac can't find the system software...so you could be right about the disk.. Another possibility which could have fried the disk is that you've lost whatever cooling is in the powerbook.  Since you mentioned about the extreme heat I'm guessing that the possible hard drive issues may be a side effect of the heat.  I'd have Apple tech guys look at it if it's worth your time and money to check out.