I've got strange problem when I'm trying to play NHL07 on my computer..!

-Vista Ultimate OEM
-Athlon 64 x2 4200+
-Sapphire x1950 Pro
-Asus M2N-e

And the problem is slow gameplay...!
Menus are too slow comparing to other computers with less powerful harware than mine. Also the game is running smoothly but in slow-motion and that makes gaming impossible...
I have tried XP compatibility mode but no help.

Anyone having similar problems?

I tried to google with some keywords but no luck...

I'll appreciate any help