From a laser-printer-quality perspective, the trouble started under her. The last really good series of laser printers they came out with (the original laserjet 4000/8000 series) were one of the first to come out with under her tenure, and based on the costcutting their immediate successors had (e.g the 4100s) it seems likely they were in response to her changes.

Their PC division was already producing cr*ppy machines before Fiorina, as was the consumer half of Compaq's before the merger.