UPDATED The machine is a 1 Ghz Compaq Presario 700 lap top running WinXP-home with all recent updates, Windows firewall disabled and no Norton or McAfee firewall installed. Connected to the lap top via a USB 2.0 port in a USB2 card is a 200 GHz hard drive. The HDD has two partitions. One partition is set up to be shared on the network. Until recently, I could access the files on the USB connected HDD from my two other machines on the local hardwired Ethernet network. (Simple sharing at the drive level as well as lower levels is enabled.) I now get error message saying I may not have permission or not enough server storage is available to process this command. See subsequent post about irpStackSize being too small. I can read other files on the LapTop's C:\ drive over the network without problem. I can also read files on the other networked computers from the LapTop. Using Windows explorer on the LapTop, I can easily view and change the contents of the USB connected HDD by selecting the drive letter. However, using Windows Explorer on the LapTop to access "network connections" of the LapTop, I nearly always get the same error message as is that displayed on the other networked machines when seeking to access files on the USB connection HDD. The problem seems to be independent of whether the files are MP3 or plain data. Updates... When the external USB HDD is connected to another computer, files on the HDD can be viewed over network. INTERESTING .... When a short cut to the external USB HDD is placed in a directory on the C:\ drive of the lap top, the shortcut can be seen over the network, but it has a white question mark on a red circular background in the lower right corner of a HDD icon. Also... between when things worked, and when things stopped working, I installed the new Norton System Works 2006. However, the problem remains even when I turn off Norton protection. Norton GoBack was turned off by clicking on icon in lower right corner and selecting exit or other appropriate option. Norton system works was similarly subsequently turned off. See later posts for cure.