PowerPC :: IBook G4 14" Is Freezing

Lately, my iBook G4 has been freezing a LOT. I'll be watching a video, filling out a form, blah blah blah, then all of a sudden mouse cursor cannot be moved. Keyboard is functionless. Windows remain without animation.

I've installed a gigabyte of RAM into my well over a month ago. Basically all throughout August it worked fine, no freezing or anything. Every now and then it would act funny after waking from sleep causing me to reboot, but that was it. However, the RAM is not installed an extremely secure fit. I tried for hours to get it to fit in a way I thought was proper. I'ts secure, it doesn't move. I took the RAM out and put it back in again to make sure it was ok. I also managed to make the plastic keyboard lock (the ones you press down to take-off the keyboard on an iBook) pop-upp and render itself functionless. That shouldn't be a big deal if I bring the iBook to Apple, should it?Anyway, my main questions are:

1. If any, what are the primary causes of such freezing in Macs/iBooks?
2. Does it seem the RAM would be a problem, or is there possibly another hardware or software problem?
3. Is there anything I can do software-wise that may remedy this? I know freezing is one of those things where the source problem is difficult to determine, but I am willing to try a few remedies for possible problems.