This evening as I tried to leave work I noticed that my key would only go half way into the doorlock. I went around to the passenger side to find the same problem. Next I tried the trunk lock, which opened the trunk and all the doors without a hitch. The only problem is that unlocking the trunk doesn't turn off my alarm! There was no way I could drive home with the horn going off the whole way. I called MB roadside assistance, and they told me how to deactivate the alarm (remove fuse 8 and 15). The problem with that is that it also turns off the door lock/unlock system. So, when I got home I had to replace those two fuses so that tomorrow morning I will be able to get into the car (through the trunk again, and then to remove those fuses again!) When I got home I inspected the locks and found white powder on both the driver side and the passenger side. I'm not sure what this powder is, but I have a feeling that someone was messing with my locks. I am so bothered right now...thanks for listening.