MBP & Lion with external monitor crashes!

I have a macbook pro 13'' (2011) and OS X Lion. But the mac crashes every time I try to boot while I use an external monitor.

I only get 2 white screens (on the monitor and on the mac), the fan gets very loud and nothing happens anymore.

The only way to boot is to boot the mac without an external monitor.

It's plugged in via HDMI and an HDMI to mini displayport adapter.

The Monitor is a Samsung Syncmaster XL2370HD.

I hope anyone has a solution for me.