OS X upgrade (Snow Leopard) caused Kernel panic

I recently bought a MacBook Pro from a friend of mine. The computer worked fine when I first got it. I decided I wanted the most up to date OS X so I tried to install Snow Leopard. Install went just fine but when I tried to reboot, as it says to do after install, I ended up with a screen that said "You need to restart your computer. Hold down the Power button until it turns off, then press the Power button again." I get the same screen every time I restart. I have been searching through different forums and found many different ways to try to fix this, but to no avail. I have tried booting in single-user mode and using the command "fsck -f" but I am unable to type anything. When the text finishes loading I get:

Mac OS version:
Not yet set

Kernel version:
Darwin Kernel Version 10.0.0: Fri Jul 31 22:47:34 PDT 2009; root:xnu-1456.1.25~1/RELEASE_1386
System model name: MacBookPro3,1 (Mac-F42388C8)

System uptime in nanoseconds: 2680620157

I am very new to Macs, this is my first one, so I need as much help as I can possibly get. Thanks in advance to whomever reads this cry of help.

Have you tried restarting with the SnowLeopard disk and running disk utilities Verify and permission repair?

Try Erasing the disk and another full install otherwise try the original install that came with it .. to rule out hardware problems.

I tried (after an exhausting battle to get the disc back out of the drive) to boot from the SnowLeopard disc, no luck. I put the disc in as soon as I power on and hold the 'D' key and nothing, right back to the Kernel panic screen. I don't have the original OS X discs either. Not a big help, I know. Any other ideas?

too boot to the cd try holding the C key right after the ding... or the Alt/Option key to get the hard drive or the DVD/CD

if you hold the mouse button right after the ding it should eject the cd/dvd what ever is in the drive.