Helping people with computers... one answer at a time.
There are some steps to try if you need to install hardware and do not have your Windows XP CD.
I bought an HP 854n media center computer with Windows XP pro. A year later I had to give it to a friend to clean it out, totally, and he said that he could give the comp back to me, but with no sound. In order to get sound, I would need an installation disk. I do not have any "winnt32.exe" like you suggested I look for in an I386 folder. Nothing is there, so what can I do to get my sound back?
The good news is that there are some steps to try. The bad news is that you may need an installation CD anyway. The good news is that it may be OK to borrow one.
These are the steps I would try:
Run that add hardware wizard. There is actually a possibility that the software required is already on your machine and that "it will just work". Admittedly a small possibility, but worth trying.
Update the drivers. Or rather, pretend that the hardware was already installed, go visit the manufacturer's site for updated drivers, and follow their installation instructions. In this case, I'd visit either the HP website or the website for the manufacturer of the sound card.
Borrow an installation CD from a friend. Presumably you already have a licensed and working copy of Windows XP and all you're adding is support for additional hardware. There's no piracy involved here; it's quite legitimate to borrow an installation CD and use it when the hardware installation process asks for one.
The moral of the story is simple, though:
Insist on getting a valid Windows XP Installation CD when you purchase your system, even if Windows is already installed.
Save that disk in a safe place. You'll need it in the future. Make a copy to your hard drive if you like, but save the CD.