iMac mid 2011 black screen on start up with fan running

I rarely have problems with my computer and last year there was once a problem where my disk drive broke. After getting it replaced my Mac worked perfectly fine as good as new. I used it before the day with no problem. I started cleaning and unplugged all the cables (I turned the iMac off before doing that). After plugging all the cables back in I turned it on. The sound came but no image and the fan started to spin fast and loudly. The mouse and keyboard where responsible and I even get the sounds by clicking escape. I turned it back off and unplugged the cable and put it on a different slot by the power cord. I waited and turned it back on and everything went fine. The image came and the fan spinned normally. I let it stay like that until it went to sleep mode. I heard the fan spinning fast and loud again and the image didn’t came back. It’s there any solution?