how to unlcock pop up blocker

If you're using Firefox, then when a site attempts to open a pop-up window, you'll see a yellow bar appear that says, "Firefox prevented this site from opening a pop-up window." (Or, if it tries to open more than on, the yellow bar will say, "Firefox prevented this site from opening N pop-up windows." where N is some number.) There is a Preferences button on the right side of this yellow bar, just to the left of the X that you would click to make the bar go away. Click Preferences, and you have the option to individually show any of the pop-up windows that were blocked, or to allow pop-up windows for that website, or to edit your pop-up blocker preferences.

As an alternative solution, you could go to Edit > Preferences and click "Content" at the top (unless it's already highlighted). The first item is "Block pop-up windows". You probably want to keep that box checked, since unchecking it would allow all sites to generate an unlimited number of pop-up windows, without restriction. However, you can click the Exceptions... button to the right of "Block pop-up windows" and edit what sites are allowed to show pop-ups. If you don't see a yellow bar when a site tries to open a pop-up window, then you'll have to use this solution. (This is equivalent to clicking the Preferences button in the yellow bar and then clicking "Edit Pop-up Blocker Preferences...".)

By the way, if the yellow bar doesn't come up when a pop-up is blocked, and you want it to (so that you are informed when a site tries to open a pop-up window, and can show pop-up windows that were blocked), type in "about:config" (without the quotes) in your address bar and press enter. Click the "I'll be careful, I promise!" button, and then find:

privacy.popups.showBrowserMessage
(you can start typing that in the filter text box, to find it more easily)

Right click on it, and toggle its value back from false to true.

(If you're using some browser other than Firefox, then please post again, and indicate what browser you're using, so I can give you instructions for that browser.)

how you unblock popups will also depend on whether you have blocker add-ons on your browser.

i have the yes! popups block on my firefox (which is more effective than the one with firefox). it overrides the yellow bar that eliah mentions, so i have to allow popups via the add-on.

That's a good point. To see what add-ons you have installed and enabled in Firefox, you can go to Tools > Add-ons.