The disclosure is for an apparatus and method for voting that are based on personal computers. All data and software, including the operating system, voting software, and original ballot information are on a single portable data storage medium, such as a diskette. During use, voting results and security-check information are added to the same portable storage medium. The apparatus also includes a tamper detectable seal for a diskette in the computer and means for officials to authorize each voter to begin voting. In one sealing system diskette removal is prevented by a blocking plate that slides into the diskette slot above the diskette and an extension fastened to the diskette is also attached to the blocking plate assuring that the diskette cannot be removed until a visible seal is broken.