When I get a website

Question

When I get a website up, I can't then get another window to upen from that site. And then i can't get out of that site because my computer freezes and I have to shut down. When I try to do that, half the screen disappears. When i press "turn off" I get an "End Program" dialogue box which says "This program is not responding". If I press "End Now" the computer will shut down.I Have an "Acer Aspire 3500" laptop.Regards.............Lynne Stokes