I've baked my GPU last week. I've set the oven to 180C and left it in there for about 8 minutes.
And miracously my GPU works again
! I've reseated it, applied thermal paste, installed drivers, and done!
I'm not sure for how long it will hold up, but at least it works again
I'd like to thank EVERYONE who participated in this thread and trying to help me.
Note: I also sent an e-mail to alienware support some time ago. The mail was received, and I was promised to get an answer within 72 hours. Just yesterday (22 days after sending) I received their reply. They just said: your warranty expired, go buy some GPU on ebay.
Not the best of support if you ask me.
Thanks again to all of you