From the latin Haddenus, condition exist when one is not able to lift arms above shoulder level to properly work on a vehicle. Sometimes comes when you are assigned a job that is above your mental mechanical level. Also when you are a complete idiot but do not know it , but still think you are the smartest person ever!
Dan: "I'm feeling like a Dinosaur today and with these raptor arms Im not able to work on this car."
Tom: "Looks like a bad case of installitis!"
Dan: "mmmmmmmm I got to go home Im sick"