Missing sound events and can't edit registry

I am at the end of my rope trying to fix this problem. My computer recently stopped playing sound at startup, shutdown, and at other occasions. I don't know what event this coincided with such as installing something new on PC. When I go to Sounds in the Control Panel, no Sound Events are listed, no Sound Schemes are listed. When I search the hard drive, sound files are there in Windows\Media; and they play when I play them through Windows media player. The PC is also hanging up on the "Windows is shutting down" screen, but I'm don't know for sure if it's a related problem, or a separate problem. I have tried it seems like 50 different to fix the hangup problem on restart and nothing works. I also found a fix on microsoft.com for adding a missing registry key: HKEY_CURRENT_USER\AppEvents\Schemes\Apps\.Default\.Default but when I try to add that key, it says "The specified key name already exists" but I don't see it.

I finally did a complete new re-install of Windows 98 SE and the sound events are still not there. I did get a new error on boot up: "Cannot find c:\windows system\regsvr32.exe" but again I'm not sure if it's a related problem or a coincidental one.

Can anyone shed some light?

 

Anyone?

Here is more information too:

There are keys missing from my registry in the HKEY_CURRENT_USER hive. I looked into restoring them, but all the restore options are too new to be of use.

I am new to messing with the registry, but when I do try to add a key, I get the message "error accessing the registry". What can I do to add/restore the keys I need?