OK, first download Firefox 1.5.0.4 from the link in my sig. This will take you to the official site, so there will be no risk of getting any spyware bundled in with the download, which can happen with third party download sites.
I think you may be under a mis-apprehension that Firefox has spyware protection built in - it doesn't. It is, however, more secure then IE, because of the way it has been written, and due to the fact that spyware / trojan writers tend to target IE, as it is still (unbelievably) the most popular mainstream browser.
The default Firefox settings should be fine, and shouldn't really need adjusting, but just make sure that the Pop Up Blocker is enabled (Tools > Options > Content), and that you have allowed pc-pals.com by using the Exceptions button, or you may find problems logging in, like you did before. Also remember to go to Tools > Options > Privacy, and using the Exceptions button again, allow pc-pals.com cookies. The Pop Up Blocker may not block every single pop up (there are some pop-unders that can fool it), but it will certainly block most of them, and I don't believe a pop up can install spyware on your computer, just by 'popping up'. To safely remove a pop up, click the red X to close the window, rather than clicking OK, or any of the other buttons which may appear.
If you found you were inundated with spyware before, then you will need to use third party spyware protection, such as Spyware Blaster, which you said you have now installed. You must make sure that you Enable All Protection for Firefox and IE, and you must also remember to periodically check for updates, unless you want to pay the small amount to enable Auto Updates, which is worthwhile in my opinion. That should really be all the protection you need, especially if you don't make a habit of visiting 'dodgy' websites, and periodically using Ad Aware and SpyBot to scan for any spyware which slips through, should keep your PC nice and clean.
Of course, you still need adequate Anti Virus protection, and a Firewall to block intrusions, and if you have all these installed, updated, and running, you really shouldn't have any problems.
Check out our newly updated tabs at the top of the screen, for lists of available Anti Virus and Firewall applications. You will find that there are still a few free ones available.