External monitor on MacBook problems...

[D34th]

Before I begin, I did search and found nothing, if something is already out there that you know of, just post a link. So my sister gave me her old LCD monitor. It is just a 15 inch Dell that has worked perfectly for the past 4 or 5 years. I got myself a mini-DVI to VGA adapter and plugged it in. At first it worked fine, was detected and I changed the screen resolution on the external to 1024x768 and after about 15 seconds of that both screens went haywire with little rectangles of many colors flashing all over the screens and then OSX quit. So I completely unplugged the monitor and tried to run my MacBook alone and I got to the desktop and the screen did it again. Now I whenever I turn on the laptop, I get to the gray screen with the apple and then it again goes haywire. I think my only option is to bring it in right? Specs are Black MacBook, 2.0 Intel Core 2 Duo, and 1.5 GBs of RAM...