Imac 27'

Hi ,
i have purchased IMAC 27 inch, with snowlepord OS , i want to install a windows OS on it ( AS DUAL OS SNOWLEPORD AND WINDOWS BOTH WITH EQUAL PARTITIONS) , which OS will support IMAC properly including all its drivers and which will be the supported Boot camp for that .
i tried the following but only lacked behind for audio drivers :-
1) windows xp 64 bit ( could not found audio driver )
2) windows xp 32 bit ( could not found audio driver )
3) windows 7 64 bit retail version ( after installation screen is black nothing comes up)

4) steps how i installed windows OS .

i had made equal partitions in snowlepord OS first then inserted the windows cd and booted the IMAC and followed the steps for installation and it installed sucessfully .
tried installing drivers from BOOT CAMP 3.0.1 but did not succeeded for audio drivers .
if there is another method of installing windows please do let me know .

5) if still audio drivers are not available for any windows OS on IMAC then suggest me the USB audio jack compatable with IMAC so that i can play sound through that .

6) i want to install any 1 of the following on my IMAC please do let me know if i can get its audio drivers from anywhere .
A) windows xp 32 bit sp 2
B) windows xp 64 bit sp 2 or 3
C) Windows 7 32 and 64 bit

please advice
regards