Multimedia Audio Controller Problem.. (Please!, help me.)

Hi!,
I'm Lito Valdez, Could anyone of you help me!?, Because before, the Operating System that I used is Windows XP Home and it has a sound, now, my twin-brother change it to Windows XP Professional, but, my problem now is that I can't hear any sound of my PC and when I looked into the Device Manager the "Multimedia Audio Controller" has a yellow question mark and has also a yellow exclamation point, and I ask my twin-brother what's happening why did our PC don't have a sound now after you change it to Windows XP Professional and he just answered he don't know what's goin on, and we have a Driver for Multimedia Audio Controller.
Please!..., Help me...
And before I forget, I downloaded the CPU-Z and the Motherboard shows this:

" Motherboard "
Manufacturer = ASUSTeK Computer INC.
Model = P4P800S-X Rev 1.xx
Chipset = Intel i865P/PE/G/1848P Rev. = A2
Southbridge = Intel 82801EB (ICH5)
LPCIO = Winbond W83627THF

And hope the information of motherboard can solve the problem of multimedia audio controller.
And just E-mail me at: lit_143@yahoo.com
I just want to say that Thanks a lot in advanced for helping me...
God Bless you...

You need to reinstall the audio controller driver set. either use the CD that came with the motherboard or download a set from the Asus website for your country. As you have not told us what country you are in I cannot suggest a suitable URL for you.