This is how it looked when I tried to restart the iMac after it crashed again on Saturday.
The techs took a look at it last week and diagnosed a broken graphics card. They put a new one in and sent it back to me. I fetched it on Saturday. Three hours later, it crashed again. I took it back to the shop yesterday and we'll see what they say this time. I hope that they can fix it before 7th of December or I'll have to buy a new one in order to play WoW.