If you have tried to log in to your PC and you get the "tree or server cannot be found" error, please check the following:
1) If your PC is plugged into the back of your desk phone, start by disconnecting the two cables at the back of the phone (phone and PC).
2) Wait roughly 5 seconds and then plug them back in to the corresponding jacks on the phone. The phone will come back up, and then you should reboot your PC.
3) Most times this will take care of the issue.
If your PC is connected directly to the network jack with no phone in between, then check the the following:
1) Check to see if the cable is firmly seated in the network card jack on the back of the PC, if it is not fully seated, push the connector in fully.
2) See if there are any led's lit where the cable is inserted (usually just above or below the jack), and one should be blinking to indicate a connection.
3) If the led's are not lit, then the cable connection is not fully seated (wall or PC sides) or the cable could be damaged.
4) Failing the above, it is possible that your PC was plugged into an inactive port. In this case you will need to submit a ticket.