No hard drive

[gorgeouslies]

Hello,
I had tried to install a grapics card in my computer when i turned it on it started to load but then the screen goes black and reads " NO BOOT DEVICE AVAILABLE" ... I have ran a diagnostics test from the f2 button and everything passes except the hard drive it says no hard drive detected. someone PLEASE HELP!!! i touched no cables or wires EXCEPT the monitor cable on the OUTSIDE of the computer

 

[ss202sl]

How can you(try to) install a new graphics card and not touch anything inside the case? You need to look at the cables attached the the hard drive and verify that they are connected, and the drive has power.