Mouse buttons not working properly

I installed 2.7 to hard disk.
I can scoot around the screen with the mouse cursor. But after a couple of minutes there is no reaction to the mouse buttons!
Then after some time it will start responding again, but just for a short time.
At the moment it does react to the left mouse button by showing a square "ballon" with a hint when I click on one of the tabs in the menu at the top. But that is the only reaction I get.

I tried Microsoft mouse and Logitech mouse. Both are USB mice.
The same PC did run Linux before without problems. I believe Ubuntu 10.4, but I am not sure. That may also have been with a different mouse as I just grabbed a couple from the mouse nest.

How should I go about to solve the problem?

Edit: I just discovered it will react to clicking one of the items in the menu at the bottom. It will open the application, but mouse still not working inside that application!?

It was announced in the upper right corner that there were seventysomething updates to be had.
So my strategy was to win the race to the updates before the mouse went lame.
After a couple of misses I made it! And that seems to have cured it.
So there goes. If you encounter the same, shake loose and get ready for a mouse race! Hope you too will win.

Maybe I could have accomplished the same by uttering some magic words in a terminal window, but I'm no Linux sorcerer.