i downloaded realtek hd audio driver exe for windows 7.but when i installed it pc restarted but there was no player(for pitch changing and all)in control panel it shows installes.what should i do
Are you sure you installed the new version? If you already had the Reatek control panel installed and you run the new executable file, it first uninstalls the old driver and control panel then reboots. This looks like it is installing the new version if you aren't paying attention.
You have to run the executable file again after the reboot to install the new version.