hard drive installation problems

hey /tech/
i just pulled a hard drive out of my other computer to try and put it on the one that i do use. heres the problem, i hooked it up and lugged it in, and when i turned on my computer it wouldnt turn on. it kept turning on for a brief second then turning off. what would/tech/ do in my situation. im trying to use it as storage, and extra space on my computer.

more than likely, your power supply is not craptacular but shittasticly tasting the rainbow.

translation: the two hds are sucking more power than the powersupply can provide