Help with kernel panic and freezing screen?

Question

A few months ago I had kernel panic screens about twice, but the problem didn't recur again for a while. Over the last two weeks, however, I've had two more kernel panics, and the screen freezes (mouse, all actions, etc) and the machine has to be manually restarted about every five minutes.
I've tested the two ram sticks, erased and re-installed the OS but had no luck resolving the issue.
I followed the link on resolving kernel panic problems from earlier threads to troubleshoot as much as possible. I don't have the original software so can't do a few steps, but on the whole have had no luck.
I don't have any external or USB devices hooked up when it fails. I do occasionally use USB pen drives, but that doesn't seem to be related. I bought a new, non-apple power source a while back, too, but also don't think that's related.
Before I bought the laptop from a friend, he installed a different hard drive, but I believe it came from another G4 Ti machine. He left two screws out of the bottom of the case.
I'm thinking mainboard or possible hard drive? Any ideas?
Also, since reinstalling the harddrive, I've had no error report message come up when the machine restarts, and there isn't an error log file, at least not for kernel panics (that I can find.) Before I reinstalled the OS, I read the error reports and they said something about kernels....but I don't remember what, specifically.
If there are other useful logs I could post, let me know and I'll find them. Are the console logs or directory service logs of any use?
Thanks in advance for any help or any advice...!
PowerBook G4 Ti Mac OS X (10.4)
PowerBook G4 Ti   Mac OS X (10.4)  

Answer 1

Hi tjk
- Thanks for the help.
I've tested the two ram sticks
How?
I took out each stick one at a time and ran the machine with a single instead of both.
I have dual 256 sticks. The original, and a Samsung which came with it when I bought it used.
In both cases, the same problem occurred.
How much free space do you have available on your HD?
If not 5GB or more, this could be causing issues.
I had about 20GB free. Now it's running with 70Gb free and still the same problems. It's an 80 GB hard drive that was installed into the PB when I bought it a few months ago. I had the machine for about three weeks first, and didn't have any of these problems with the other hard drive in it.
I don't have the install disk, so can't run the disk utility repair, correct. I've also not been able to get the PB to boot from the disk instead of the hard drive. It brings up only the hard drive as a selection to boot from, and spins up the OSX DVD, then ejects it each time.
...not sure why...I've been holding down option when restarting to boot from other drives -- if there's another way to boot from the disk, maybe that would work...
Have a look at the Orange Ribbon Cable Issue/Fix and see if
it might apply to your PB. Which Ti do you have btw?
This is a really interesting link and for a bit I thought it sounded exactly like the problem...but I have the original TiBook, 500 Mhz so the trackpad cable doesn't run through the same spot. Maybe there's something else shorting out or pinching underneath...I'll take a look, but I'm not necessarily hardware savvy enough to know what to look for.
Thanks again for any suggestions.
PowerBook G4 Ti Mac OS X (10.4)