|A sound problem like yours is often caused by wires that are broken inside the speaker cord, most often near the plug that plugs into the computer - if the insulation is intact for the broken wire(s) the broken wire ends may have an intermittent connection - both speakers may work when the cord is in certain positions, only one works when it's in other positions....|
....but that doesn't accounf for your oddball 0 Drivers problem.
The POST will halt when it encounters certain errors.
Plug the transceiver for the wireless keyboard into a USB port on the BACK of the case if it isn't already plugged in there.
If you have an external hard drive, don't plug it into a USB port above or below the USB port the transceiver is plugged into.
Remove the AC power to the case.
Remove the left side panel as seen from the front of the case.
Make sure all cards in slots are all the way down in their slots.
Restore AC power and try the computer.