Strange Case Swap Problem

[FlyboyHD]

A couple of years ago I purchased a HP Pavillion P7-1414  which has a MSI-7778 Motherboard with quad core processor in it.  Pretty nice machine over all.  We recently upgraded the RAM from 6 GB to 16 GB and we bought a new case with a 500 watt power supply.  Every time we swap the mother board into the new case the computer goes haywire into this extremely slow boot up mode and it takes out the boot sector of the hard disk requiring us to re-image the drive.  Very strange it is so slow that it takes over night to re-image the drive and is still re-imaging today as I type this.  When we take the mother board and put it back into its original case it re-images quickly as it should and everything goes back to normal.  What could the problem be and why is Windows 8 so finiky with this motherboard and a new case?  Thank you.

[FlyboyHD]

@FlyboyHD What case and power supply did you get? Are you trying to use the factory HP Windows 8 image on your new motherboard? That's what's causing you to have to reimage the drive, because you can't use the factory Windows 8 Key with a different motherboard, because the key HP used, is licensed to the motherboard that HP used.

we kept the hp motherboard and hard drive and just put them in the new case. the only thing that changed is the powersupply and the case. 

The PSU is Rosewill Stallion Series RD500-2SB 500W ATX12V v2.2 Power Supply. and the new case is  APEVIA X-Hermes X-HERMES-GN Black/Green Steel ATX Mid Tower Computer Case w/ Side Window-Green

[FlyboyHD]

Are all of your standoffs in the right place? Proper power to everything? same SATA port for the hard drive? same boot devices hooked up?

yes same everything from the hp case. the only thing that changed was the power supply and the case.