Check Your DxDiag Settings
Install Direct X 8.1
Get All The Lastest Windows XP Updates Mainly The Driver's
Are You Sound Cards Driver's Unsigned They may cut in and out prior to that
roll back driver's
get the lastest sound card driver's i cant tell u where from because you havent tould me what sound card you have prior to whether its extended or on board
clean install boot via the Cd from the BIOS Clean install instead of upgrade
install SP1 For winxp
although try changing sound cards which you said you did do it this way change them via extended and via onboard you cant change onboard i know but what i mean is set it to run sound via onboard see if that works
are the JP on the sound card set correctly
are theyset to one cdrom only have they been plugged into the correct cdrom outlet
or correct onboard outlet
Test to see if when the sound cuts out its just for the stuff on CD's Via through the CDROm nor through the HDD if so you need a speaker or CDROM drive update
This happens to my friend who has the same sound card with Carmon Speakers
the lastest pci update patch fixes it all
Flashing the bios if that didnt help then
i would get winxp updates prior windowsupdates.microsoft.com
i work for -=DaRk_sHaDoW=- Technology Corp Of Australia and as a computer technition i have assumed that the JP's are set wrong
the updates are not installed or not installed correct
the driver's are not digitally signed
the motherboard does not support your sound card
you pci slot has been corrupted or set to the wrong frequency
TRY Enabling DMA mode 33/66/100/ although that only really display
try ajust the program/game settings prior sound
check updates for the games/movies etc.......
Check to see if the sound cuts in and out only when playing via a cdrom
GOodluck hope this work
my website will be up in about 1month or so with tech support on