There's many problems with this =P but can be fixed:
Stuff you should do:
+ I recommend you get rid of McAfee, as it has been reported to be useless/malware itself =P BUT i could be wrong

+ Get a firewall installed if you don't already have one.
+ Check to see if you have a drivers disc for the adapters, if not search on Google to see if you need a driver
+ Remove/Uninstall any of your adapter's programs/drivers so that we can start fresh =]
+ Disable any other internet connections that are enabled on your computer
+ Virus scan, a must. I recommend AVG.
+ Run a scan through Spybot Search & Destroy (Download
here)
+ Run CCleaner Registry Cleaner (Download CCleaner
here)
Than after that reinstall the adapter (with the drivers if you need them) you would like to use, than see if it works =]
IF It doesn't work:
Can you tell me your PC specs and what adapters you are using?