I have had this problem for some time and unexpectedly solved it while trying to solve a problem with Excel 2010 on an HP machine.
In excel I had trouble selecting the first tab in a spreadsheet. It behaved like I clicked with the right mouse button even when I did a left mouse click.
This site gives the solution to that problem (I can't access it right now):
http://www.mrexcel.com/forum/excel-questions/538503-excel-2010-worksheet-tab-problem.html
The solution was to update the HP wireless assistant software on the HP machine from here:
http://h20566.www2.hp.com/portal/site/hpsc/template.PAGE/public/psi/swdDetails/?cc=us&lang=en&swItem=ob_84194_1&ac.admitted=1384980053457.876444892.199480143
