How are you supposed to use a home network when using OpenDNS? If you set it as your DNS on the router it hijacks even Windows file sharing traffic so you can see computers on the network but when you click on them it won't go. You can only access them by IP address, but this isn't acceptable. If you ping the computer name you get COMPUTERNAME...ISPSERVER.com or .net or whatever. How do people deal with this?
Please ensure you are using the double slashes before the computer name in windows explorer address bar (\computername\share). If you do not, explorer will think that you want to go to an internet site. This is the default behavior of explorer.
Also, it sounds like you may have a 'search domain' set up. This will attempt to search that domain for computers (e.g. computername.opendns.org).
If you are trying to use your own internal DNS servers, you should have your router use the internal servers and those DNS servers should be configured to forward unanswered requests to the OpenDNS servers.
The only other configuration is to use the windows host file to define the ip address of the computers on your network. The issue with this is that the computers need static IPs.
If you just set this up, open a command prompt as and admin user and issue a ipconfig /flushdns
That will clear the local cache and ensure you're getting the right result from the DNS.
The most likely cause of this is that you have no DNS at all for your internal network, so you're relying on the old NetBIOS/WINS lookup method. Windows only uses this method if the name you enter does not resolve in DNS.
Because OpenDNS has "wildcard" DNS support (i.e. when you type a nonexistent address, you get redirected to an OpenDNS search page), now all possible addresses resolve in OpenDNS's DNS. This means that Windows won't fall back to the old NetBIOS/WINS method and you'll end up trying to connect to one of OpenDNS's servers, rather than your internal network.
The solution to this is to get DNS working on your internal network. Firstly, make sure you're using your router as a DNS forwarder and not going straight to OpenDNS from your PCs (i.e. configure OpenDNS on your router and leave DNS automatic on your PCs). Second, make sure your router supports resolving DNS for the internal network and this is enabled. Thirdly, ensure that all PCs have valid hostnames set (Windows is more relaxed than DNS about what you can use in hostnames, use only a-z 0-9 and '-').
Hopefully this should put you on the right track...