Can Electronic Voting Machines Be Hacked?

The answer is YES, - according to a professor from Princeton! Anyone who had access to a Diebold voting machine and its memory card can take only minutes to install a software that would generate an inaccurate vote count and can delete itself at the end of the election day!
The worst thing would be if the software is inserted into a central machine, the fixed card could act like a virus and change vote totals for an entire region.