sorry did not mean to loose you along the way.
the idea is you update your main chipset and use windows update to gain access to the correct usb drivers and your devices should then work.
now i just checked your motherboard its using a sis chipset, so you can go ahead and just use windows update.
now on some sis chipsets they still need the usb2 driver installed even under windows xp.
if you no longer have the disk that came with the motherboard/computer you can download the lot from here.
http://www.asrock.com/mb/download.asp?Model=K7S41GX&s=nso to cut this down to size.
use windows update till no more updates can be found,
click the above link, download and install the usb2 driver
windows will tell you if its needed or not.
then shut down your firewall, anti-virus and try loading your problem scanner and cam again.