We have an Windows NT 4.0 network here where I work. On three computers, I am having problems sharing things. Each computer has Windows 98 on them. I have each computer up on the network. From each computer, you can see all of the other computers on the network and access their files, drives folders, and printers. You get on the Internet on each of these three computers a LAN. Each of these three computers has a 3Com nic (10/100MB Ethernet NIC 3C905B-TX)in them. Under Network properties I have TCP/IP and Netbeuii protocols configured correctly, File and printer sharing for Microsoft Networks with both boxes checked. I have each IP Address, subnet mask, default gateway, and DNS configuration figured correctly. The problem is this, I cannot share anything from these 3 computers. I have tried and tried to share folders, drives, files, or printers and I get this message "Either there is no default mail client or the current mail client cannot fulfill the messaging request. Please run Microsoft Outlook and set it as the default mail client. Well, each PC has a default mail client and they are figured correctly. I have even switched back and forth form Microsoft Outlook to Outlook Express (just moved the mail account back and forth) and still no help. I have tried and tried and tried form these particular 3 computers and still I get the error message "Either there is no default mail client or the current mail client cannot fulfill the messaging request. Please run Microsoft Outlook and set it as the default mail client." Can anyone please help me with this? What is the deal? All of these computers have installed product updates, security updates, Internet Explorer 6, installed on them from Micosoft Windows Update. Please help!!