Operating system won't load

Sounds like the directory or permissions are damaged. Have you backed up your data prior this happened?

Hi BrodyT, Welcome to Apple's Users Help Users Forums.

Time to but a FWHD. OWC is often recommended. I use Superduper which when purchased, $27.95, allows smart, quick, backups.

a brody may come back w his own list of recommendations. I find Dantz Retro' a bit much.

Try to see if you can boot from the Installation disc by holding C key, when you start the computer?
if that works, try and run disk utility and repair disk permissions on the hdd.

is it possible to redownload that stuff without paying as long as you have the account information?

Nope. When you signed the agreement, it was pointed out that it is your responsibility to backup everything.

You might be able to recover it with Prosoft Data Rescue and a Firewire external hard drive of at least the same size as your existing hard drive, or if you have another Mac, to use Target Disk Mode to see if the drive is visible from that other Mac.

http://www.prosofteng.com/ makes Data Rescue

Target Disk Mode is explained here:

http://docs.info.apple.com/article.html?artnum=58583

If your Mac is invisible using Target Disk Mode, then you have to use a data recovery software.

My backup FAQ* explains various backup options:

http://www.macmaps.com/backup.html

* Links to my pages may give me compensation.