Alienware X51 problems after moving to new case

Hi Everyone,

last week I upgraded my old X51 with a new gfx card and power supply while moving it into a bigger case.

Everything runs just fine except for two smaller things.
1. On boot up I get the failure message: Alert! Power Supply Failure.

Strike the F1 Key to continue. F2 to run the setup utility.

If I hit the F1 Key everything boots and runs smoothly.

2. If I shut down the computer everything turns off except for the power led on the case itself.
I have to use the little switch next to the power supply to get rid of the glowing light.
It's off though when I put my computer to sleep mode.

Does anyone have had similar problems after moving to a different case and knows how to fix this.

Thanks a lot!