I was having email and download issues so did a reinstall of Win 10 along with drivers.  Have an unusual problem: a) downloads of large files is slow and often fails ; 2) can not send emails with attachments through Gmail though they will go out under my Verizon account.  Emails without attachments send fine;  3) verification of third party apps is slow and often fails with Google.  After a lot of trial and error I decided to unplug the ethernet cable and go wireless - all works fine.  So issue seems to be ethernet related.  Tried another ethernet cable - did not fix the issue.  My laptop works fine so I expect that the issue is with the Optiplex and not the router - either the driver I'm using or the card on the board has gone bad.  Not sure why I can send attachments when attached to ethernet using Verizon but not Gmail. Any thoughts.