Access denied to Windows 7 drives

I have some problems with access, printer status and usb connections not showing.
First my setup:
I have three computers on a home network
1. An old machine running XP SP3 (32-bit). To it I have connected, via USB, my Epson R300 Photo printer and a FreeAgent external drive. On it I a running ZoneAlarm Security Suite with the firewall turned off for the Trusted Zone. Two drives with two partions each .
2. A new Windows 7 Professional 64-bit machine with virtual XP-mode installed. It is running the built-in Windows firewall. On the virtual XP I am running the free basic Zone Alarm and the free AVG virus program. One drive with two partions (C and D).
3. A laptop with Windows XP SP3 (32-bit) and Zone Alarm Security Suite with both firewalls active (Internet and Trusted zones). One drive with two partions (C and D)
All three computers are connected directly via Ethernet cables to a Linksys router.
All drives are set to be shareable. All are in the same workgroup (MSHome).

Now the problems:
A. While I can see the drives from each computer (most of the time, not always), access to the Window 7 drives is always denied from both the old machine and the laptop. Why? Sometime my external drive shows the directories but I can't access the files.
B. I can not print from the Windows 7 machine. The printer shows up, is set to be shared, but the status is offline. How can I turn it 'on'?
C. If I put a memory stick in a USB port on the Windows 7 machine it does not show up in explorer. Why?

I have tried a variety of things, as suggested on the net, but to no avail and if I had any hair to tear out, it surely would be gone by now.

Does anybody have any suggestions and could step me through these setup problems?

 

Thanks, TonyT.
I tried those steps before I posted here. It seems to work for some people and not for others. My problems are mirrored by posters Mike (July 9) Sudz (July 10 and 13), Joe (July 21), Fuzzmaster (July 25), William (August 3) to mention a few replies to the geeks tutorial.

Any other hints?