Why is my PS3 slim 320 GB overheating after I cleaned it?

So here's the problem:

I decided to clean my PS3 slim a while back. Opened it up carefully and bought a can with compressed air to blow all of the dust out... I guess this is where it went wrong.

After I blowed everything out I closed the PS3 again (didn't open up the internals any further because it was kind of complicated to do and the black part with the fan inside is closed off in my model) and I turned it on. After a couple of seconds it gave me the message that it was overheated and shut down... Was scared to try it again... Did a couple of days ago but it gave the same problem. A friend of mine told me that it may be due to the humidity of the compressed air that I broke something. Do you guys now what it could be?

Thank you in advance.