Installed VB, internet doesn't work correctly on host

[bman7]

I installed VirtualBox yesterday, created a virtual machine, set up Ubuntu, and that's it. That evening, I noticed that websites would randomly not work, or display wrong, but it went away after a refresh.
It's still happening today, about once every 15 minutes, and it sometimes takes up to a minute until it works again. I haven't installed anything else within the past few days, and the internet works fine on every other computer using the same connection. I'm using Windows 7 64-bit with a wired ethernet connection.

[noteirak]

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