I do not know if this caused the problem or not, but I dusted my desk and ever since my computer's speakers started making a thumping noise (I call it a rat a tat tat noise) when they are on and my DSL modem connects. The noise stops if I either unplug the modem or shut the speakers off. Also, my head started hurting whenever the modem is on. No problem before. WiFi is shut off. What is causing this and how do I resolve the issue?