Drivers for PCI device

Hello everyone I have a Compaq Presario A902TU notebook PC to which I uninstalled the Windows Vista operating system and I have since xp professional.

But I can not find drivers, I have been 4-5 days without sound on the computer also in the Control Panel / System / Hardware / Device Manager tells me "PCI Device" and puts a question mark and exclamation.
Not to do and I'm desperate.
If someone were kind enough to explain what I have to do what would be .....

Install Everest Home, draws an abstract, look at the names of the devices and download page manufacturer's device, the driver for XP.

That's the thing I have already installed but I can not find it either. Please tell me some other solution.