last time 3 of our DELL PowerConnect 3024 switches were completely hanging and we don't know the reason. we could not ping the switch and all machines connected to this switch. restart didn't help! after disconnecting of all machines, rebooting the switch and connecting again, was ok. knows someone about this problem? we have die software version 220.127.116.1191 installed on the switch. hardware version is PC-3024-00 should I upgrade the switch?