shuts down and restarts every 5 to 10 mins.

Frizzie, "but gets very hot . " means that you are overheating the laptop. First make sure that when you operate the laptop, the airvents are not occluded. I would suggest that you get the service guide first. Go to the device page, scroll to "Tools" and click on the blue "here" in this link "Service Guide located HERE (as at 30/12/2011)" Page 196 of this manual will show you how to replace the fan, but in your case it may only need cleaning and a new application of thermal paste. While you disassemble it, make sure that you clean the airvents properly too. Hope this helps, good luck.