sounds now have echo effect :S help me please..

A couple of days ago, I was installing a new game on my
system. Durning the install, the "Windows Update" message
appeared and I was taken back to the desktop. Ever since,
any sound my computer makes has a slight echo to it
(except during games). This problem has continued even
after restarting or shutting computer down. I'm not sure
it's serious, but it IS rather annoying. If anyone can
help me, I'd gladly appreciate it.

Thanx,
--TRENCH--