Couple of days, sure. Some doosies.
WHAT'YA GOT?
A graphics program that kicks the living shit out of VGA Master and Paint Man. Deadly too.
HOW?
Copies portions of itself into Video RAM and treats it as a TSR. Next program you load gets infected from Video RAM and spreads from there. Undetectable unless you're running debug at the same time and looking for it. Then it stealths itself into all V-RAM applications and spreads outside the O/S.
TRIGGERS?
I forget the exact trigger mechanism, but it gives constant parity errors. Nothing'll run.
OK! LOOKIN' GOOD.
Also have a few Lotus utilities, a couple of games.