Whenever I try to view my workgroup computers, there always a message saying that workgroup is not accessibe. Contact your administrator... iThe same happens when I try to use printer sharing. Please help.

Xp or vista

Here is a couple things to check out

Make sure your firewall has file and print sharing
Assuming your using XP
Start, settings, control panel, windows firewall and the exceptions tab
Look for 'file and printer sharing' and make sure there is a check mark in box, click OK
Open 'network connections' in control panel and in the general tab make sure check is put in file and printer sharing

On the computer you are trying to see, are the drives shared?
If not make sure they are