Xbox360 + acer 23" pc moniter HMDI to DVI-D problems

Hello, i recently bought a 23" acer moniter that can display 1080p. so i tried to hook up my xbox 360 with an DVI-D to HDMI on 1080p. The first time it worked perfectly, when i restarted my xbox there was no picture on the moniter. i tried different methods like plugging in a new set of DVI-D to HDMI cables. still no picture. I took my RCA cables and plugged it into a hdtv and worked fined. So it wasnt the xbox 360. i plugged a laptop into the moniter using VGA so it not the moniter. Im guessing its the hdmi input on my xbox or the DVI-D input on my moniter. Can anybody help me?