Is there any way to completely secure a notebook PC from other computers in a home wireless network? It's not outside hackers but untrustworthy roommates I'm concerned about, getting email passwords, online banking info, etc. I disabled file sharing, set the connection to "public" as if I'm at a public wifi hotspot, and bought a too-expensive Geek Squad plan in order to see if there were any keylogging programs on the computer. The guy said it hadn't been hacked.
Earlier on before I knew about disabling file sharing etc. I know they got into my email since I overheard them discussing it. I wondered *how* they might've done it. Before I got my notebook PC I was using the main, communal computer in the house; could a knowledgeable person have gotten passwords from there? One roommate used to work with computers and knows others who might be able to do a lot more than the average person.
Give your computer a Workgroup name none of the others have - leaving it as WORKGROUP or MSHOME will make it vulnerable. Make yours unique with upper and lower case letters and a couple of numbers. It prevents access to the casual network neighbour but also prevents file and printer sharing but a determined hacker will usually be able to find a way in so Pyree's suggestions are definitely necessary even if you change the Workgroup name.