I wanna install Windows XP in a Virtualbox on Ubuntu 13.10, I will install it only for being able to use a programs of the government for inputting taxes ( the Argentine government hasn't make programs for Linux yet) ,it doesn't use internet, I'd like to generate the file and then send it trought internet but from Ubuntu; and play Pes 2011 (it doesn't use internet too) . Do I need to install an antivirus or anything else in Windows? I'm afraid viruses can infect Ubuntu,though I won't use internet from Windows.