MacBook pro malfunctions when running certain performing certain tasks
I have a MacBook pro 2011 with the following Specs
Ever since I upgraded to latest Yosemite Edition. I am having al lot of problems using this Mac. At times its running ok. Then all over of a sudden it starts malfunctioning when running applications lets say Adobe Acrobat, or accessing certain website eg Youtube. When It starts malfunctioning it will restart itself several times prompting you to enter password and looping over and over again(Sometimes this could go on for over 10 Mins until it officially boots). During this time it will either display blue screen at instances or blurred screen.
This malfunctioning is not specific to a particular application or website, For example I connected an ipad to charge and the same thing happened. Its becoming worrying to me since I can not run anything. There is no interval at which this happens, It can function well for two, three days, then cycle starts.
Could anyone kindly help me to sort out this issue??
Thanks
Boniface
MacBook Pro, OS X Yosemite (10.10.4)