When browsing I often find the bck button doesn't work. If I click on a link no problem so I doubt its the mouse. Why would links work but the back button not work? Any magic settings to adjust.

OH , BTW , it happens very often but not all the time. Lets say over 50% of the time no back bottun functionality.

What O/S and What Browser are you using?

maybe you spilled some food on your keyboard and it's just gunked up

Its win7 and IE9.

Please do not say to use firefox. Been there , done that many times over.

Its when I click using the mouse that it doesn't work (upper left hand corner blue arrows) .

To the right I think is an arrow that will do the recent history, use that and go back to where you want. Some sites make it so you can't just click back.

Its not site specific. In fact sometimes I go back and forth on a site and then after working for several times , it starts not obeying the back button click.

I have the exact issues you described with the back button.
Try clicking the back button only once and waiting instead of continuously clicking like a mad man.
Posted from my iPhone/Mobile device

Put the mouse on the back arrow, hold the left button down and the history should appear, scroll down to where you want to return to and let go of the button.

It looks like its a common problem out there. Seems to be related to the sites you are on. If a site is heavy with advertising hittin the back button is actually cycling through the sites the ads were downloaded from. You have to hit it a few times to get it to go to the actual previous page.

have't found a fix yet....but you are not alone.

Does the Internet Explorer 9 back button not work correctly for you? - Windows 7 Forums (http://www.sevenforums.com/browsers-mail/231976-does-internet-explorer-9-back-button-not-work-correctly-you.html)

Not alone....Misery loves company. :)

Good to know its not just me. At first I thought the mouse was going bad.

Oh well , that's life surfing the net.

you can open things in their own seperate window
that way you can close them from the task bar