Internet explorer reboots computer

Ok here is the problem when I go to any web page but my Yahoo the browser works fine for a while then reboots computer.If I go straight to MY Yahoo when opening browser it reboots computer. I have repaired then upgraded browser .Turned on Java , installed visual basic scripting, upgraded directx to 8.1, checked for viruses and I can’t seem to figure it out please if you have any suggestions let me know.