Sometimes scripts make Firefox lock up.
 

Sometimes when I'm browsing the web, pages with scripts will make Firefox lock up. It doesn't have to be a badly coded page, for example GFF and YouTube will both trigger the problem. It only happens sometimes, and a reboot will fix it.

A little history. I recently built a new PC, and I'm really happy with it most of the time. As far as hardware is concerned, I'm almost sure I don't have a problem. Just for the sake of offering complete information, you can see my specs here. When I first installed Windows on this machine, I must have done something wrong because I got this kind of problem (and others) all the time. The computer wasn't usable in conjunction with the web, and I reformatted.

I created an nLite CD with SP3, all the latest hotfixes, a few usefull apps and stuff slipstreamed in. After I installed, it seemed for several days like all my troubles were over. Firefox was behaving itself, and the machine was more responsive in general. That's still true, most of the time... but occasionally the problem does come back.

So what is this? Can I fix it? Should I post a complete list of everything I have installed? What might help the collective minds of GFF solve this mystery for me?

Event logs. Post application and system logs in EVT format here, please.

What kind of lockups are you experiencing, the entire application coming to a screeching halt, so that you have to kill it in the task manager or occasional freezes that will pass after a few seconds? The former could indeed indicate an underlying problem with your installation, while the latter would just be par for the course with Firefox, owing to its aging, single-threaded architecture.