New
#11
If the PC runs fine in Safe Mode then the issue is likely a driver. Check System Recovery Options if you have a System Restore point from before the problem began as Windows Update may have delivered a problem update or driver.
If not while I Safe Mode try as many of the Troubleshooting Steps for Windows 7 as possible as these may reveal the problem. I'd first establish a Clean Boot, uninstall and change to one of the recommended lightweight AV's which never give problems, disable that strange Sound card driver to see what happens. Then scour the logs and other system resources suggested.
But I think I would not waste much time before I deleted all partitions during a booted install to Clean Reinstall Windows 7 sticking with those steps which have been used by over a million consumers to achieve a perfect install without a single complaint, or anyone returning with any issues who stick with the tools and methods given.