Q: Can't get past kernel panic

Boot from your Snow Leopard DVD. If you still get the kernel panic, then you have a major hardware problem. Take it in for service.

If you can boot successfully from the Snow Leopard DVD:

Repair the Hard Drive and Permissions

Boot from your Snow Leopard Installer disc. After the installer loads select your language and click on the Continue button. When the menu bar appears select Disk Utility from the Utilities menu. After DU loads select your hard drive entry (mfgr.'s ID and drive size) from the the left side list.  In the DU status area you will see an entry for the S.M.A.R.T. status of the hard drive.  If it does not say "Verified" then the hard drive is failing or failed. (SMART status is not reported on external Firewire or USB drives.) If the drive is "Verified" then select your OS X volume from the list on the left (sub-entry below the drive entry,) click on the First Aid tab, then click on the Repair Disk button. If DU reports any errors that have been fixed, then re-run Repair Disk until no errors are reported. If no errors are reported click on the Repair Permissions button. Wait until the operation completes, then quit DU and return to the installer.

If DU reports errors it cannot fix, then you will need Disk Warrior and/or Tech Tool Pro to repair the drive. If you don't have either of them or if neither of them can fix the drive, then you will need to reformat the drive and reinstall OS X.

Now, boot the computer into Safe Mode and operate for a while to see if the kernel panics cease. You can

Visit The XLab FAQs and read the FAQ on diagnosing kernel panics. Also, see OS X- How to log a kernel panic. Locate the panic log and post it here for us to examine.

OS X- About kernel panics

Exactly when do the panics happen? Immediately after you restart? Do you get to the Desktop at all or past login?

Can you boot the computer into Safe Mode and see if that get's past the panic? If not, then you have a hardware problem. Most likely a bad hard drive, but could be a bad motherboard or a dysfunctional memory module that passes POST but then fails after the computer starts up.

We might have gotten farther if you could use the optical drive and boot the installer DVD. Hope you get it straightened out.

If you take it in for service you can have them either fix that or replace the mechanism.