I have a Gateway MX6421 laptop purchased second handed and given to my children for use with basic school assignments, etc. I installed Windows XP Professional, went to Gateways website and downloaded and installed all of the necessary drivers based on the serial number of the laptop. However, after doing a serial number scan using Gateways utility, the model number listed(MX6421) does not match the outer case serial or model number(MX6425). I would guess that the mother board has been replaced with a Gateway MX6421 during a repair at some point during prior ownership. Also, I have no sound and upon further investigation using device manager I discovered that several devices are highlighted yellow with a question mark and listed under the heading "Other devices". Those devices are as follows;

?Other devices
?Ethernet Controller
?Mass Storage Controller
?Multimedia Audio Controller
?SM Bus Controller
?Video Controller (VGA Compatible)

What options do I have for correcting this problem? The Gateway drivers should have corrected the problem I would assume yet they did not. I am at a loss concerning what to do next. All help will be great appreciated.