My computer is off, but the FDN and Link/Act lights are still on for its channel on my network switch. Is it affecting my network, because when my computer is off other devices on the switch lose network access?
Network cards sometimes stay active after a computer is switched off in order to receive WOL (Wake On Lan) commands. These are specially crafted packets that allow a computer to be awoken across the network.
You say that when your computer is off your other devices lose network access, do the computers still lose access when you disconnect the lan cable from the computer to the switch?
It is possible that you have a faulty network card, which is spewing bad packets onto the netowrk.
In what way do your other clients lose network access?