Toshiba Satellite E105

I am having a problem with a Toshiba Satellite E105. As it boots, it goes into a loop in which the screen will get lines across the top and bottom. The lower left hand corner of the screen starts becoming brighter and brighter until it looks like it burst then the process starts all over again. This cycle takes about 3 to 4 seconds. There is 1 or 2 seconds between cycles in which you can use the mouse or anything else. After that everything looks up until the cycle is completed. I'm thinking this is a motherboard problem but am not completely sure. It is on Vista and I was able to boot to a Win 7 CD, but the problem was still there. That tells me it is not the OS. Any help or suggestions would be appreciated. Thanks