Very puzzling, I concur. Frustrating too. I'm glad it is a Windows problem and not a ReadyNAS problem, but it is also making it much harder to figure out
Yes, I can attach from a borrowed work laptop, and have though it only ever got about 6MB/s over it's GB interface, even with the 2 directly connected, even when copying from the internal HD - also tried external USB drives with similar results. Both the laptop and my desktop claim to be the same version and SP of WinXP, though I don't really trust the exactness of the info from Computer>Properties.
I've compared these settings:
1. Windows Firewall was turned on, but turned off for the eth0 and also had several exceptions (DNS, DHCP, UPnP, etc.). On my home desktop I've reset everything to be the same - had to add all those exceptions manually - and while the desktop now gives the Windows red-shield-X warning that the firewall is turned off, RAIDar's Browse still doesn't work, ditto mapping a network drive which still says "The network location cannot be reached.", again false as RAIDar and ping both work and I bet the web interface works as well.
2. I also compared all services between the two machines and came up with these lists;
Desktop missing: QCONSVC, RegSrvc, Spectrum 24 Event Monitor, SymWMI Service (manual/off), Windows User Mode Driver Framework.
Laptop automatic: WebClient, Secondary Logon, Remote Registry, Print Spooler
Laptop additional: Ati, AVG7, IBM, Infrared Monitor, db, VMWare services
Besides the ones missing from the desktop, I reset the rest to match Disabled/Manual/Auto and rebooted to no additional effectiveness. As for the missing ones, I'll see if poking at the internet turns up any downloads.