Check to see if there are any connections that came loose when you were fiddling around inside the PC. You can also head to the manufacturer's support site to see if reinstalling the sound card driver fixes the issue.
Some people like to be very hands on and get involved with every little aspect of their computer, while others just want something to do it for them. Registry Mechanic can handle the detection, repair, and prevention of registry problems automatically, or it can ask for your direct input