virtualbox.org

I just installed on a new Windows 7 Pro machine with Windows XP Home installed as the Guest and am able to run some legacy 16 bit programs successfully. I am able to access the D: drive on the host by using the Shared Folder setting, I can also access the G: drive on the host- but it gets assigned as drive E: and it has to be G:

I've removed the G: Shared Folder drive and am now trying to access it by sharing from the host. I set drive G: as shared on the host and I have a user account there that matches the name and password of the login from the guest. On a totally separate Windows XP desktop I am now able to see the G: drive on Windows 7.

However, on the WIndows XP Guest [my Network places] I cant see any shared drive and I don't even see the host machine. Pressing "View workgroup computers" gives an error - mshome not accessable

From your description, it seems you are using regular network shares. Make sure you've set the networking mode to either Host-Only or Bridged and that you proper network settings on your guest.

IIRC the workgroup changed between xp and w7. They need to be in the same workgroup as well.
xp= workgroup by default
w7 = homegroup by default

Thanks - I had fixed the workgroup name problem already - changing to bridged fixes it - though I have no idea why- since its been years since I messed around with hardware networking details, [and it also fixed another problem that I'll start another thread to discuss]

I bet you were in NAT mode before - that mode is only meant for basic usage, like web browsing. Anything a bit more specific would require a proper network config.
In case of network shares, it is because it relies on being on the same subnet and/or having a reachable IP, which is not the case for NAT on one side of the connection.