While one could comment your Subject Title needs help, the Forum Tip should be heeded. It reads "Tip: If you are asking for help to troubleshoot a computer-related problem, please be sure to include all the necessary information (ie: operating system, model number, hardware, software, etc) that will help others identify your problem for a speedy resolution."
The usual loss of sound is simply because Microsoft does not install drivers for your hardware. That's not their job. You may need to identify the make/model of the machine, call the maker or do whatever is needed to find and install the audio drivers.
In some cases such as with Aureal sound cards, you get to replace the sound card.
I've upgraded from win 98 to xp but i don't have sound.
When i go to volume controller i get the foll. message" there are no active mixers available"
What do i do?