I have solved problem on Vista 32 bit. This is what I have done.
First you have to uninstall NET Frame work and remove all traces of it. Restart your PC.
Install NET framework 3.5 again from Microsoft which suite your OS. Restart your PC.
Then uninstall ATI drivers and remove all traces of your ATI software. Restart your PC.
Download drivers which suite your OS Vista 64bit from this link: https://a248.e.akamai.net/f/674/9206/0/www2.ati.com/drivers/9-5_vista64_win7_64_dd_ccc_wdm_enu.exe on your desktop and install it from there on your PC. Restart PC.

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Potpis