Hard Disk Crash?

[MacNCrash]

I have a older (2006-ish? White, not chrome) iMac, Intel Core 2 Duo. It has been freezing up more and more over the last few months, until it got to where I could only run one app at a time, if I was lucky. Even that was very slow - click, go do dishes before another click, slow. Had upgraded OS about the time it really went south and assumed I'd overextended my RAM. Bought a new iMac with intention to wipe and reinstall OSX on the old one and keep for the kids to use. It took 40 HOURS to reinstall OSX! Then it failed to boot. Ran all the usual easy things, permission repair, disk repair, fcsk says it's great. Finally ran Apple Hardware Test and it returned a code. What do I do with the code? I can't find anything anywhere about reading the codes. Do I have to pay someone now? Should I just buy a new HD? Is it even worth it?