default event sounds problem

hi to all

i installed some software (total recorder) and some of its add-ons but it
has caused a problem which i cannot resolve.

basically, each time i added an add-on, the system sounds would change and i
would have to delete the scheme 'windows default (modified)' in mmsys.cpl

when i reset the windows default sound list, by selecting the default sound
scheme, all the speaker icons from the program sounds would vanish and i have
no system sounds at all.

i have tried several restore points but they all fail for some reason, so is
there any way of restoring the system sound scheme at all, rather than adding
each one back again by hand.

any points would be very helpful...

thanks