What do you mean by “suppressed” ? No one else reported such a problem. Actually, I really don’t see the connection between your sound problems and skins. The only skin that uses internal sounds is LCARS, and I don’t believe that you even tried that one. Skins made by Alwil guy Martin are completely the same like all those made by other skin makers, available in avast! skins download section. Every single skin maker used exactly the same technique and program to make skins, which is SkinBuilder…

Go to Windows Update site, and see if they have some newer drivers for your sound card… if your crashing issue is related to sound drivers, than you have to download latest drivers for your sound card.