Did this device come preinstalled in your computer at the time of purchase or did you buy it later, then add it to the pc?
With the vague info you posted, all I can suggest is to use our Simple Search Wizard
(the HOME button at the upper left corner of this page), to see if it's posted in our driver database or to see if anyone else has requested this same driver.
Or visit the 3Com website
to see if they offer a driver.
If it came preinstalled in your pc at the time of purchase, you should be able to get support from the manufacturer/vendor of your pc. No one ever knows how to create a proper request.... because they fail to include proper details about the device and the computer/motherboard it's used in.