Internet connection stopped working inside guest

[manvic]

Host: Windows 8.1
Guest: Windows XP

The Internet connection from inside XP worked OK but suddenly stopped. I cannot remember anymore if it happened after an
VB upgrade or not. The tip on the "double monitor" icon (that indicates the activity of the network interface, and which appears greyed out) says: "Adapter 1 (NAT): cable disconnected."

In the Settings: Network menu, Adapter 1 is attached to NAT. I've tried all other available options but couldn't restore the connection to the network.

The upgrade to VirtualBox V. 4.3.30 and then to V. 5.0 didn't improve the situation.

For testing purposes I created then a second virtual Window box, without loading an OS into it, and this time the tip on the "double monitor" icon (not grayed out this time) says: Adapter 1 (NAT) cable connected.

Unfortunately, the re-installation of all things in the guest is a time consuming process, this being the reason why I would like to reconnect my original virtual box to the Internet. TIA.

[manvic]

In Oracle VM VirtualBox menu

Devices -> Network -> Connect Network Adapter

solved the problem.