If you don't want to encounter the hassle of setting up virtual machines (and if you're not familiar with it), it's best to just clean install a new OS on a bootable pen drive (Linux distros preferably) and install just the lan drivers and browser on that OS. Afterwards, you can go ahead and create your paper wallet
I prefer to keep it offline forever, I now use a
Knoppix DVD and an USB-stick with anything I need from Bitaddress.org.
If your computer has 8 GB or more, enter this when booting Knoppix:
After about 15 minutes you can unplug the DVD and run completely from memory.
To be completely paranoid, type this in a console:
sudo swapoff -a # this disables swapping
sudo ifconfig wlan0 down # this disables Wifi
sudo ifconfig eth0 down # this disables your primary ethernet
Direct your browser to localhost:631 to configure your printer.