I just bought a old mac mini to start my ios dev. The mac mini has a DVI port, so I connected to my Dell 24" display which has a DVI connection. But my mac wont boot. Actually, I dont even know, if it is booting or not. Because my monitor did not show anything, as it did not get any signal and went to standby mode immediately. My questions are:

1. Do I have to connect keyboard and mouse to mini in order to boot?
2. Even I did not connect keyboard and mouse to mini, I will still see something on the monitor, won't I? something like a error message, telling me no any keyboard found. To make it clear, my display works fine with my PC.
3. I tried with my Microsoft USB keyboard and an IBM USB mouse. But I did not see any difference, i.e. nothing could be seen in the display.
4. Does it mean I have to buy keyboard and mouse from "Apple" to make it work.

Can someone help me and give me some hints. Thanks a lot in advance!