In the company that I work, we have Windows 7 installed on all PCs. We don't have internet access through Windows but can set proxy settings in Firefox and can thus access the Internet.
I installed a virtual box on one of these Windows 7 machines and Ubuntu 14.10 but I have problem with accessing the Internet.
How can I access the Internet through the proxy server via an Ubuntu virtual box running under Windows 7?
you have to make a Network Bridge in Windows (between VBox Host-Only Network and the Controller connected to the Internet)
In Virtualbox you can leave the Adapter at NAT
I´m using this with my debian-vm. Additionally I added the Network-Proxy as system-wide Proxy in my VM.
Good Luck!