Bridged Adapter Stopped Working

[allanc]

I am running the newest version of VirtualBox on a XP PRO sp3 guest on a XP PRO sp3 host.
I have Comodo Firewall 5 installed on both.
The Host is on a VLAN on a Cisco managed switch.

At one point, the Guest could access the Internet using Bridged Adapter or NAT.
At that point, the Guest Additions were installed.

Now, the NAT still has access but the Bridged Adapter can no longer browse any site.
The icon in the taskbar displays 'connected'.
Disabling both Firewalls does not resolve the problem.
Pinging the host or other IP addresses does not resolve.
I have also uninstalled VirtualBox and reinstalled it with no success.
I think (but am not sure) that the Bridged Adapter stopped working when I uninstalled the Guest Additions.

[allanc]

Can anyone offer any assistance ... please?