What is the best and most reliable of these two browsers. I've had IE for
some time - it had been slow and had problems, so a few months ago I
switched to Firefox, just from reading posts. Now I am having problems with
it. All of you out there who are far more familiar with this stuff would
have more knowledge on this than I do. I have Windows XP service pack 2 and
1 gb of ram.
Thanks in advance for your opinions.

What version of Firefox do you have? Go to Help > About Mozilla Firefox
to find out. If it's not version 1.5, you should go to
http://www.mozilla.com/firefox/ and download the new version; they
generally fix a lot of problems with each rollout. In terms of your
computer specs, Firefox will run on SP2, and 1GB of RAM is more than
enough.