I recently purchased a C400 with an integrated 3Com 3C920 ethernet card.  I cannot maintain a consistent connection with the internet.  Repairing the connection does not help.  The only thing that seems to work is to re-boot the laptop.  I'll regain connectivity for a few minutes and then it will go out again.  I've updated the BIOS and 3Com driver.  Nothing seems to work.  Can anyone offer any assistance?  I'm about to throw this laptop out the window.