I think it is unlikely that it is a Group Policy restriction that is causing your problem. Without Group Policy in Vista Home Premium, the only way that this setting could have become active was you changing the registry (which you haven't) or a virus. I think that a virus doing this is extremely unlikely. This group policy, from what I can make out is for local CD drives, not necesarily networked. This setting does not come under NetworkConnections.admx (a Group Policy administrative template to do with networks) In fact, I have not found this under either spreadsheets, though I definitely think it is a group policy. Under group policy, I would count this more as a networked folder.
Normally for group policies, 1 is enable and 0 is disable (binary), but this is enabling or disabling the restriction
, so to disable the restriction, to allow access to CD drives, you set the registry value at 0. Setting the value at 0 was therefore sensible, however setting the Default value at 0 was probably less so (I know you read that, and I am not blaming you in any way). Leave it there for now though, it might help.
Here are some things to try:
- Set up one shared folder on each computer, and see if you can access it from the other computer.
- Disable all firewalls TEMPORERILY. This is a security issue, so enable them again afterwards, even if this fixes the issue. We can set up exceptions later.
- Make sure the network settings are correct on both computers, it should not make a difference, but it is worth checking.
- What Security software are you running? Does it have a buit in firewall, and is the firewall enabled? Is the Windows firewall enabled? Is UAC enabled? What are these settings on both computers?