Forgotten Password to be unmasked or revealed

There're are many bookmarklets on the net that get the password using some JavaScript. I cannot test with Internet Explorer, but just one out of many: Show, Reveal, View or See Hidden Password Field Text.

"Most routers possess a hidden Reset button that restores its state back to the default.

You can find that button in your manual, and use it to reset the router to a blank state, which will include resetting the password to the default as specified in your manual.

However, all customizations or settings that you have done in your router will be lost."

"If I am reading your question correctly, it is the password for your broadband (issued by your ISP) that you have forgotton. If none of the tools suggested by @Arjan work easily, then I would just phone your ISP. They will be able to tell you the password.

Out of interest, if your router is correctly configured, why do you need the password?"