FireFox and Flash dance the "CPU lock" dance!

I am NOT a happy web application user. My main computer is a Windows XP box with a Pentium 4, 2GHz CPU, and 1.5G RAM and yet I still get multiple second response times from FireFox. And, God forbid, that I should watch a video via Flash because then I get no f'n response for several minutes as FireFox and Flash dance the "CPU lock" dance!