Sound problem withXP Home

I do not hear the sounds of Windows logging on or logging off, the Outlook Express incoming mail sounds, my Sony Clie sync completed sounds, etc. I do hear my Quicken sounds and music, etc. Also, I used PC Doc to check and everything seems ok including the device drivers. I reinstalled the sound drivers but nothing seems to help. I clean antispyware at least once daily and use NAV to scan daily and defrag daily. Any help would be greatly appreciated.
Thank you.