Problem with DVI to HDMI

I purchased a new gateway SX2800. The only video output options are VGA or HDMI. I am using a a gateway 22" TFTLCD monitor Model FPD2275W. It has every input but HDMI. With my old computer, I always used a DVI-DVI cable. The recommended screen setting is 1680x1050. I always have run it at that setting. I was originally using a VGA cable but ordered a high quality DVI to HDMI cable. When I install it, the higher the resolution I set it the more distortion I get. At the highest level, it reminds me of a bad UHF signal with lots of red. Everything works fine if I use the VGA cable. It has built in video and uses Intel Media Graphics Accelerator as the driver. It is also a Vista 64 bit system. Any ideas why the problem? Are the two components incompatible?

It was actually a bad connection on the monitor. Although the plug was in, I had to back it out slightly then it was fine. Thanks for your reply.