Those consequences resultant when one's computer is either knowingly or unknowingly maliciously invaded with malignant viruses and/or spy/ad-ware programs.
May be used in a sentence:
As a statement: "Kazaa really fisted my computer."
As an exclamatory outburst: "Hot damn, that porno site seriously fisted my system!"
As an observation: "Damnit, these viruses are really fisting your computer!"