You probably reached a tipping point with the power supply. It just doesn't have the "phumf" to get going, it's underpowered. Try removing the one or both CD power connections and then connect the HD and see if it boots-up, but be sure the bios is reset for no CDs present. If it works then or improves, just replace the psu with a compatible but higher rated wattage. The psu is also showing its age after 2yrs.. replacement should be at least a 350W or better and a namebrand one, not a cheap one. be sure it will work in your system.
Be sure that the HD jumpering is proper. If you use master/slave setup or CS, then it is correct and using 40pin&80 conductor IDE cable and/or the SATA setup is correct.
hp pavilion a1112n. 160 gb samsung . 1 gb ram. 2nd hard drive 200gb westen digital.
He's my issue. 3 days ago i got the blue screen of death. It said "kernel stack inpage error". When i attempted to reboot, i get "sk boot disk error". opened up cpu and after about 10 try's and playing around with settings(changed 2nd hd from slave to cable select)got it to work. as a side note the cpu boots with no issues when the 2nd h/d is unplugged. but i plug in both hard the both disapear during boot-up. few days pass with everything working perfect, and it happens again, same issue, i also notice that my second hard drive is not spinning, almost like if was getting no power. I ordered a new power supply from Hp but they sent the wrong one. Is it possible that the power supply is failing? maybe its not enough power for 2 drives,i disconnected the 2 cd/dvd drives and it still would not power up the 2 hard drives at the same time. its 250 watts for 2 hard drives, 1 cd burner and one dvd burner. worked fine for about 2 years but im thinking it might just be a simple power supply issue. any thoughts out there????