I can't establish a remote internet connection with my D-Link DCS-6620 Internet camera with one of my computers. It works with the other computers. I tried one computer with Vista and another with XP and can't make a connection. Don't know why?

Is your ip is static or dynamic?If it is dynamic,then you have to reset your modem or else if it is static,then ask your ISP to change your ip.To know your network ip address visit Ip-Details.com .

Please follow this process for IP Address:-
http://setuprouter.com/router/dlink/dcs-3110/login.htm

try thi http://members.driverguide.com/driver_search.php?q=D-Link+DCS-5300+Network+Camera&si=45ac3d3fb166f28324fbc3f3e07671d2&st=1293173485&si_prev=a5cc51902d69a00e2259df9efdc54601&gqm0=D-Link+DCS-5300+Network+Camera

check whether they are using automatic IP addressing . it may be they are using the same IP in static mode so that one won't connect.

you need to do some port forwarding and possibly use a static address assigned to your camera.
remotely is this context means being able to access the camera feed when the camera is behind a router. in essence what you are trying to do is this:

camera ------ (private) router (public) ---------- internet ------- remote user.

the private side or your router is the one that you control, the private side is what is known as being "behind the router"
your router requires to be able to forward traffic from the public side for this you need to do some port forwarding.

a practical example that you can follow can be found in this website if you look into the Support Resources>FAQ section under the title "How do I remotely view DCS-6620 or DCS-6620G series cameras that are behind a router or gateway?"

the article from dlink goes like this:

For each camera that resides behind a router or gateway, three ports must be forwarded by the router to obtain both audio and video. If audio is not desired, only the HTTP port will need to be forwarded. The three default ports are as follows:

• 80 (TCP) HTTP Port (allows access to web-configuration and transmits video if other ports are not forwarded)
• 5002 (TCP/UDP) Audio Channel Port (transmits synchronized audio)
• 5003 (TCP/UDP) Video Channel Port (transmits synchronized video)

These port numbers will need to be changed in the camera configuration on each additional camera that is added behind the router. Port numbers can be changed from the Advanced > Network screen.

please look in to the section described within the link to see how camera and router need to be configured.

I hope this helps!

There are several possible answers, but you need to supply more information. You did not say how you get to the Internet, which company, cable, DSL, or satellite? Most satellite companies will not allow cameras to be seen outside the network.

Download the software on a computer that is connected to the internet and transfer the file(s) via a flash drive or via your network (if connected to a LAN).

Uninstall Microsoft Silverlight

If you are using Trend Micro Virus protection It will cause the video to be blank.

From wat ya say it seems to me that you are loosing ya signal sometimes? perhaps a "Better" antenna on the Base unit may help, one with a "High Gain" Also perhaps ya need to check and clean any connections etc. Hope that helps.