Well dear all friend.
First thing you should keep in mind while applying this thing is that you should install the mac os x v3.6 i.e 10.6.2 version.
if you don't know how to install it then here is the link
well it also should be dual boot..i mean to say.. you should have both win 7 and mac os x.
now download the 10.6.7 combo update from the apple site or any other source...
you can download it from here too
then after download this file you need one more file to download that is
now after downloading this two things..
you need to boot to mac os x ..
then after install the combo update...but make sure you don't restart it.
please after install is successfull please dont click on restart button ...
rather open this 10.6.7 update file which will contain the "legacy for 10.6.7" package ..install it and then restart the computer..
after restarting you will notice that your computer screen will show you the apple white screen stuck..well it fine... no need to worry...
now again restart and boot to windows...
now make sure your computer has mac drive 8 installed on you win 7.
well if you dont have it then please download it and install it.
well after installing this software it will allow you to access the mac partition.
then after open the drive in my computer in which you have install your mac and go to system/library/extensions/
and then delete all the kexts files which starts with "ATI"
after deleting all the kexts just restart the computer and boot to mac...your mac will be running smoothly...