Can multiple users connect to the same computer using a VPN? I have one PC at my office and 7 salesman. I need them all to be able to access a program on the office PC. Not all 7 will be using application at the same time, but 2 or 3 may attempt to use it at the same time. Is this possible? If not through a VPN what other options do I have? Some will be running Windows XP some will be running Windows Vista and some will be running Windows 7

You say PC so I take it that it runs a client OS? If so it will not allow more than one desktop session. How are you planning to run the program? If you just need access to the files you can solve it by adding a firewall/router with VPN capabilities, like Cisco ASA 5505 and others. Then the VPN would terminate in the FW and not in the PC.