TBH, it sounds to me like there is something wrong with your Windows install! On face value it sounds kernel and/or driver related to me, possibly something to do with network drivers? I say that as you note that the browser locks up first, followed by a system freeze. But I'm only guessing...

We have thousands of Windows based users and no one else has reported this. So I suggest, if possible you try to test it on another Windows machine and see if you can reproduce the issue. I run Debian locally, but I did quickly test on Win 7 and I can't reproduce it.

Perhaps another thing you could try, is accessing your VM from the browser of a different device (e.g. another PC on the same network, or a smart phone or tablet if you have one). If my guess is correct, then the other device should work fine but your Win 10 desktop should still lock up. The browser will possibly still lock up briefly (as the Win system crashes), but once it has crashed, then it should

I would have suggested that perhaps it's a Virtual Box bug, but the fact that the same occurs with VMware, suggests to me that it's more likely a Windows issue.

I guess one other thing you could try, is installing from ISO instead of using the OVA. It shouldn't really make any difference as the OVA is built from the ISO, but perhaps the default driver that our OVA is trying to use is problematic on your system? Perhaps simply swapping the virtual NIC would do the trick?