G1) I was infected by the Jerusalem virus and disinfected the infected
    files with my favorite anti-virus program.  However, Wordperfect
    and some other programs still refuse to work.  Why?

The Jerusalem virus and WordPerfect 4.2 program combination is an
example of a virus and program that cannot be completely disinfected
by an anti-virus tool.  In some cases such as this one, the virus will
destroy code by overwriting it instead of appending itself to the
file.  The only solution is to re-install the programs from clean
(non-infected) backups or distribution media.  (See question D10.)


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