it really depends on how well you know each system, if your good at Windows use firewalls and stuff and anti virus, because if you arent to good at Linux, stick with Windows for your online time untill you get better aquainted (sp?) with Tux. i use SuSe Linux and in there is an option that lets you select what your PC shows up as, you can make it seem liek your running Windows 98 with IE if you want, a few more details about your PC would help a bit, but for the most part, go online using firewalls and stuff, and while your on read about Linux security and when you get good youll be fine and remember, Linux likes to be toyed with so have fun and read alot about Linux, but if you can reply with what Linux distro you use and a few details that would help.