Can't highlight text, double mouse clicks............

Please help, when I select (highlight) text with the mouse, as soon as I release the mouse button the area I have highlighted becomes "deselected".  I have this problem with ie, excel, word..........  also one mouse click will generally grant me a double click that I didn't want.  For example, if I click the back button on is, it takes me back 2 pages, not the 1 I want!  If I double click my ie icon on the desktop I am blessed with 2 ie windows opening............  I have been trying to work with excel and I am ready to lose my mind.  I can't keep text highlighted to copy and paste.  It has been doing this for a while (months), not sure when it began.  I have read of this problem on another site but no solutions were offered.  Please help save my machine from ending up in the city dump!!!!!!!!!!!!!!