right click delay

When I right click a folder I get the menu immediatly but when I double click or right click a file like a txt file , jpeg pdf or doc I get a delay of about 7 seconds without any activity on hard drive before the menu appears or in the case of double click before the the programm associated with that file starts to open. I tried on my other computer but they seem to act much faster, so there must be some setting somewhere.
This may not seem a problem but gradually it started to annoy me so if there is any help I would really apprecate it, thankyou

mario

 

The first solution could have been the closest since in those idle moments the CPU usage was not effected, I tried to remove the effects as explained but did not help, so I did a repair install and everything is OK now , thank you for your help.