W 8.1 pc -HP envy h8-1420t, 8GB ram freezes up after 15-20 minutes

w 8.1 pc -HP envy h8-1420t, 8GB ram freezes up after 15-20 minutes of usage no matter what program I'm using.

Video card AMD Radeon HD 7670 Ver 13.52.0.0.

Wait & wait sometimes it starts working again other times I need to reboot.  Didn't start when I first upgrades to 360 but has gotten impossible now.  My other (older) 5 PCs are doing good with 360 its only my newest PC. I keep getting message that Norton is doing work in the background.