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If the 'patch' is the root case then back-up your user files, uninstall WoW and reinstall it. I assume that other games are fine. To rule-out some conflict run MSCONFIG, select Diagnostic and test. To rule-out some virus use ESET -> http://www.eset.com/us/online-scanner
and use the latest ATI/AMD GPU drivers -> http://support.amd.com/us/Pages/AMDSupportHub.aspx