A free Memory Test prog you can find at www.memtest86.com takes several hours.  You should let the computer warm up to see if as Victoria says, you are having a heat problem, before testing the memory.  

When booting look to see what the CPU temp is If you have setup info.  Should be 120 and less to 90 F after two hours operation.  150 to 200 is hot, and may cause the computer to lock up.

As Victoria mentions, clean everything, even the Power supply if possible.  If you cannot reach the inside, use compressed canned air with a long soft haired  artist brush.  

For the CPU, get new silicon heat dissipating paste like Artic Circle, the better quality the better heat dissipation. 

If none of the above and defragging the hard drive does not work, then back up your Vue materials folders and then reinstall VUE.

jankeen.com