The former issue sounds like OS corruption, potentially due to malware, but there's other possibilities as well. The latter issue could be something as simple as a corrupt driver or it could be a sign that the motherboard is on the way out. So, a good quick test is to grab a Linux LiveCD distribution like Knoppix or Ubuntu. These can be run without having to install anything on your computer, though you will probably have to disable secure boot in the UEFI/BIOS before it will boot. Once you get the Linux distribution running, use it to test the audio. It may not sound quite as deep and rich as you're used to, but if you hear anything at all you know the hardware is fine and you have a software issue.
If you find a hardware issue, stop right there, do not pass go, make a backup of important files and then immediately call up HP and set up a repair ticket and hope they actually honor the warranty. When you get it back, check and see if the update problem still exists. If yes, you can try scanning for malware, but odds are it's in too deep and the amount of time it'd take to recover to 100% far and away outstrips what it would take to just format and start over from what you describe. You could also have a failing HDD, which if the tech at HP's subcontracted repair center is paying attention, should find on a routine diagnostic check and replace. That's why you always have backups of important files. Otherwise you learn the hard way.
I have an HP Envy Notebook computer with Windows 8.1 and audio by Beats by Dr. Dre. Now, my computer has been doing this very not cool thing by tell me it has 6 updates available, however when I update and restart, not only does it take about 2 hours to initially install (?) the updates, but at around 97% completion, it has a message saying it cannot complete the changes and then proceeds to take another half an hour to undo everything it just did. This is one of my problems.
My other ailment is my precious audio. This just started recently. On my desktop, the volume control says mute. If I click on it, it troubleshoots audio problems but it can never find the problem. So I click on other assistance, being adamant to fix my audio. HP helpdesk has steps like "Typing 'find and fix audio' into search charm, clicking playback, and then it will troubleshoot" but my computer cannot find the problem.
Then HP helpdesk suggests I set my playback to default speakers by "Typing 'sounds' into the search charm, selecting change sounds, clicking the playback tab in the Sounds menu, selecting my default speakers, then hitting configure" but my default speakers do not show up under this tab. I think my computer forgot it has speakers or something. Any useful knowledge will be very appreciated!