Dos Boot is the first part of the 7th episode of season 3 in Dexter's Laboratory, originally airing on June 7, 2002. In this episode, Computer suffers from a virus and Dexter must go into the motherboard to destroy it.
Dexter is working on Computer when all of a sudden, she stops working and starts getting shut down. Computer has a virus and she dies on Dexter. Dexter needs to go inside of Computer to stop the virus and so he suits up in a suit and goes in there. When he does, he finds that everything seems to be going perfectly okay. Then he comes across a hole in Computer's binary patterning and it is revealed that it came from Mandark who is inside of his computer giving it a virus. Mandark explains how Dexter opened up a email that he sent to him carrying himself as a virus. When he got in there, he destroyed Computer's binary patterning and made her die. Dexter and Mandark get into a fight which Dexter wins, then all of a sudden everything falls apart and they both fall down and fond themselves on the home screen of Computer. Computer has come back to life, but they are stuck inside of there. Dee Dee then walks into the room and starts playing around with the computer. She makes girly pictures of them and prints them out and hangs them up on her wall.