How in the world can a computer get that dirty? Also, are those rats alive or dead? In any case, those are indeed some nasty computers.
Nothing new! Been there and done that. You all should work for corporations or aerospace industry (factories) and see how bad their systems look inside. Worst then those images, but you get used to it!
Not just the aerospace industry, but in many large corporate networks full of cubicles, carpet, and people traffic and you will find computers like this. But the worse can easily be home computers. I wish I had pictures of one computer I got in. It was a 3 year old Gateway that had never been cleaned and the user (a neighbor) said it kept crashing. I knew by looking at the vents it was going to be a mess inside, but I did not expect it to be so bad. The computer sat on old shag carpeting, he smoked like a chimney around the computer, and they had 3 cats. It was truly a biohazard in there. The crud was so thick and sticky, it had to be scrapped off with a paint scrapper. The CPU fan was totally caked over and could not move.
I cleaned my PC recently (last weekend). I have a water cooled PC so it takes literally the whole day to take everything apart get all the dust out and then put it all back together. I was quite surprised that nothing was growing inside the tubes - seeing I hadn't cleaned the liquid in a year. Seriously snowed with dust inside the case. I am surprised nothing has died on me.