Why is my USB keyboard not recognized correctly after an annual cleaning?

I have a 5 year old Das Keyboard 4 Ultimate. Once a year I take it apart and clean it out with an air duster and cotton buds (Q-tips). After this year's clean, it will no longer connect straightforwardly: When connected to any USB port on the monitor, where it has happily worked for years, the three lock LED's will illuminate for a fraction of a second, and then go dark. There is no USB connection chime. The keyboard does not show up in Device Manager. The monitor continues to work as a USB hub for webcam and mouse dongle just fine. If I connect directly to any USB on the laptop with which I h

Question by Mark on Super User, licensed CC BY-SA. We show a short excerpt and link to the original thread as credit.