Problem unscrewing K9A2 Platinum mobo from case

Question

I need to move my K9A2 Platinum mobo ( along with peripherals and add-on boards ) to another computer case. All has gone well with removing all my peripherals and add-on boards from the old case but when I have tried to remove the mobo a two of the screws cannot be unscrewed. They were held to the bottom of the old case with metal clips. I could eventually remove the mobo by forcing out the metal clips but no matter what I try I cannot seem to unscrew either of the screws from its metal clip. Whether I hold the metal clip on the bottom of the mobo in place and unscrew the screw, or whether I hold the screw in place and turn the metal clip on the bottom of the mobo, the threads holding the screw to the metal clip are not unloosening the screw from the metal clip.
I seem stymied. The only practical solution I can think of is to cut through the area holding the metal clip on the bottom of the case with some sort of small blowtorch-like device, if something like that exists, but naturally I am afraid any heat I apply will damage the mobo.
Thoughts ? Suggestions ? I really need to get these clips off so I can transfer my mobo to another computer case I have since it is my main desktop computer right now, although I will soon be building another system

Answer 1

 Another thing you can try is carefully pull on the to put pressure against the screws and then see if it helps to get the threads engaged. If no luck then your only other choice is to carefully drill out the screws and hope the drill doesn't slip and damage the MB.
 I have had similar problem in the past and putting pressure against the screw like that usually does the trick.