I think I fried the hard drive
I tried upgrading to a new OS and now the drive seems fried. I get the apple and the swirly thing, but it won't boot up. My Superdrive is dead and I tried reinstalling the OS from the disks on an external, but no matter what I tried, it won't read the disks (used all the configs for the keys to start up from external drive). I think I may need a new harddrive. How hard is this? I went and bought a brand new 21.5" imac but want to give this to a friend.
imac, Mac OS X (10.4.2)