No Audio Output Device Installed!

I'm probably missing the obvious on this one but appreciate any help I
The audio drivers on my Vista Home Premium were accidently uninstalled and
all attempts to get Vista to reinstall them have failed, I have the right
drivers on hand and Vista does recognize them but while Vista attempts to
install them the system comes back with a timeout error. Vista will even get
the correct drivers from online but always times out as it attempts to
install them.
There's no useable system restore points to jump back to & no other driver
to roll back to. The Device Managers Sound properties has this dialogue
box...

"The drivers for this device are not installed. (Code 28)
This operation returned because the timeout period expired.
To reinstall the drivers for this device, click Reinstall Driver."

Hitting the reinstall driver button just results in the same problem
happening & same error message. Can you just manually put the drivers into
the correct Windows folder??

Or am I looking at reinstalling Vista along with everything else?
Isn't Vista fun!