Can someone hack into my computer if it is not connected to the Internet?
Answer: If your computer is not connected to the Internet, there is no way for information to be transmitted to or from the computer over the Internet. If you have a modem connected to a phone line and have your computer set to receive incoming calls, it is theoretically possible for someone to hack into it, but extremely unlikely.
The only way for someone to hack into a computer not connected to the Internet or a phone line it is to physically use the computer. While manufacturers may include chips that uniquely identify your computer, they do not put in chips that transmit any kind of information about your system. Any personal information you have on your computer is stored on your hard drive and is safe as long as no one accesses it. Therefore, it is a good idea to require a password to log in to your computer. It is also wise to erase your hard drive and "zero all data" before selling or giving your computer to someone else.