An Average of 7 Crashes a Day... help!!!

Right, i have now been the owner of a 12" ibook for just over a year (just long enough for the warranty to run out of course). Deciding that 256 ram wasnt enough, I went and bought another stick of 512, which went in and was instantly recognized. However, a couple days later it all started. Now it just crashes non stop. The most common ones are when everything simply freezes, leaving you with no option but to turn it off and back on again. The other, more frequent problem is the grey screen that pops up informing me that "You need to restart your computer" in about 5 different languages. When the machine runs, it runs perfectly, but then it just seems to want to crash for no reason. There is no pattern to it that i have figured out yet anyway. For example, yesterday while watching a DVD the grey screen crash occured twice. Is it the memory or could it be something I dont know about? And another thing, how do you uninstall programs from OSX? this has also been driving me mad....
thanks in advance.
oh yeah im using a 12" ibook/768/30/1.2 tiger

I am almost sure it's that new RAM you installed. How long ago did you install the new stick of RAM? Either it's defective or your machine does not like it. Is the new RAM new enough to take back as defective?

That gray screen with the 5 languages is a Kernal Panic. Very often they are caused by defective RAM.

Take out the new ram you added and put the old back in and see if it still happens. If it no longer crashes it was the ram and needs to be returned or exchanged. Did you get the right ram speed? I think it is supposed to be PC2700 for that iBook but you should double check. To uninstall programs, simply drag them from the applications folder to the trash can, and do the same if there was a dock icon. The only exception to that technique is a few programs such as Microsoft Office and a very few others which provide you with an uninstaller, but even those still usually uninstall with the drag to trash technique.