Snow Leopard corrupted main Mac HD,..can't boot to it HELP Please!

Question

Boy did I have a day today!!
A couple of days ago, I achieved and re-installed OSX 10.5. Upgraded to 10.5.8. Then, I installed Snow Lep and upgraded to 10.6.2. Now, I did all of this in safe boot since at the time, my graphics card was broken. I got a new one today and everything was fine. After I installed all the OSX stuff, some of the programs did not work, such as iCal (said this version does not work with the current OSX version) Spotlight (no response) and Preview (no pictures, just a blank screen).
I called Apple and they told me to re-install SL. I re-started from the CD and the install started. BUT, then a window came on saying the installation failed. So, I restarted again, and same thing. Then, I decided I just leave it for now and just restart and log back in. WRONG! No more Mac HD icon. I now was only able to boot from the CD (no Mac HD icon). I then partitioned part of my other internal HD and tried to install SL on that. It failed on that one as well.
THEN I tried to install 10.5 AND, it worked. Sorry for that long explanation.
Now, I don't think I can get back into my main Mac HD( Can't boot from it). I can get into it from this partitioned one to get files. What are my options now? Can I try to do a repair? If not, I guess I have to do a clean install of 10.5? If that's what I have to do, how would I go about that? Disk Utility, select Mac HD and erase? If yes, which erase? Don't erase Data? Zero out Data? Or is there anything I can do to fix my main drive from the internal Im currently on so I can boot back in?
Thanks in advance for help! Greatly appreciated!!
I get the feeling that I got a corrupt SL install CD.

Answer 1

In a situation that complex I can tell you what I would do (after roughly 25 years doing tech support). I would get all the data files off the drive to another hard drive. I would then back them all up to a second hard drive and I would verify that they are there and that each of those data drives was "good" using Disk Utility and Disk Warrior. Once I had all the data, including email, desktop files, documents, music, pics etc etc and I knew they were backed up independent of the problem drive I would wipe the drive entirely - partition it. Then I would erase it with zeros - a potentially long process but worth the effort IMHO here. Then I'd reinstall 10.5, update fully and go to snow leopard if that's what you want to do. In that process I'd search on any hardware that could be problematic as well as third party software that could have issues. Whether it's 10.5 or 6, I'd update fully and then connect one of the external data drives and copy back documents and other data after all your applications were installed and updated and known to be working. That is a long, obnoxious process. I keep my own "time machine" by having an external boot backup that I only overwrite every once in a while when all is acting solid. A second boot drive backup is made regularly before any major app installation or before any OS update. That way can easily roll back to a recent state or if needed roll back a bit further. All my data are backed up to external drives with the critical stuff backed up twice. It's easier than it sounds with CCC or SuperDuper and in the long run can save hours upon hours. I've been in your shoes and I wish you the best of luck. As long as your data is intact, everything else is just a time consuming pain in the butt.
your SL install should do a thorough checksum verification before it installs. it's not impossible it's still corrupt but unlikely ...assuming you let it do the entire verification.