The viral infection may have caused more damage than a simple "cleaner" can fix. Though the cleaner may have removed the virus payload, the virus may have caused additional irreversible damage to some of the files. In that situation, important processes might hang when, for example, they make a call into a library function that just isn't there anymore because the virus overwrote it and the cleaner removed the virus.

The other problem is that, once you're in the position where one virus has downloaded another virus, and it's snowballed like you described, you can never be sure that there isn't some other piece of rare malware in the mix, still lurking there, that your scanners didn't catch.

Finally, you said that it seemed like the problem might have been a Realtek audio driver issue, but that a driver update didn't fix the issue. How far down that rabbit hole did you go? In a case like this, just updating the driver isn't enough. The driver's updater program might not be smart enough to know that it has to fully replace every file in cases where it got virus-damaged. If you still think the problem might be in the audio driver, try fully uninstalling the audio driver, both from APPWIZ.CPL and from DEVMGMT.MSC. Disable the audio device altogether. Then see if web browsing works without freezing. If that works, then you've narrowed it down.