My question is, am I right or wrong in this thinking.

Pooh Bear

With your approach, you're using a linux "box" which is much less susceptable to intrusion. Less susceptible, yes, but not completely safe. You're presumably doing so with no antivirus running in the virtual machine instance. It's true that there's some protection if the virtual instance can't write to the hard drive, and everything goes away when the virtual instance is closed

There is malware that can be harmless on one machine but then seek out vulnerable nodes on the network. That could be your Win machine, still running and still connected to the network while you're using the virtual linux PC as an additional node on your network.

Again, my knowledge is limited but your approach seems like bulky overkill to me. If you spend your time on reliable sites and you have a strong antivirus/anti intruder running, the precaution is unnecessary. If you're paranoid about internet risks, just use linux for surfing. I think your halfway approach is a false security, you'd probably be better off either entirely with linux and antivirus, or with Win (OSC?) and antivirus.

Secure Web Browsing: Running your Web browser under the protection of Sandboxie means that all malicious software downloaded by the browser is trapped in the sandbox and can be discarded trivially.

See link,

http://www.sandboxie.com/