Comp will not boot, blinking cursor

[Ryansayshello]

Okay so i tried installing a hard drive from an older computer of mine into my new one today -- after a few hours of screwing around with it i said forgett it and put the original hard drive back onto the mother board now all i get is a blinking cursor... any ideas?

 

[zephead]

if you're lucky, you missed a jumper or a cable. doublecheck said parts, with attention to detail. if you're not so lucky, you may have broken or at least damaged something. if you're really stumped, take it into a local pc repair shop. it will probably cost you between 10 and 30 dollars (USD) to have the problem diagnosed by an experienced technician.