All Workgroups have become invisible on Win2k SBS Domain Network

I have a Dell Windows 2000 Small Business Server (WIN2k SBS) that has been running smoothly for nearly 10 years. I also have a NAS device that is on the network and is set up as workgroup device.

Up until last week, I could browse under My Network Places-Entire Network-Microsoft Windows Network, and it would list both my Domain Controller network and also the workgroup. Now it only shows my Domain Controller network. HOWEVER - if I do a manual search on My Network Places for the workgroup, it finds it and I can access it and all of its resources. The workgroup name then appears in the tree, but if I click on the workgroup name, I get "Workgroup is not accessible. The list of servers for this workgroup is not currently available". Thus it seems that the workgroups are fully functional, just invisible.

I have done the following PRIOR to having this problem:
Installed Microsoft iSCSI Initiator on the Server, then uninstalled it (couldn't get it to work right)


New IPSEC errors have since appeared in Event Viewer, on server bootup -
Event Type: Error
Event Source: IPSEC
Event Category: None
Event ID: 4281
Date: 5/29/2011
Time: 3:59:59 PM
User: N/A
Computer: SERVER1
Description:
Unable to allocate required resources. Initialization failed.
Data:
0000: 00 00 00 00 01 00 54 00 ......T.
0008: 00 00 00 00 b9 10 00 c0 ....¹..À
0010: 01 00 00 00 00 00 00 00 ........
0018: 00 00 00 00 00 00 00 00 ........
0020: 00 00 00 00 00 00 00 00 ........

Event Type: Error
Event Source: Service Control Manager
Event Category: None
Event ID: 7026
Date: 5/29/2011
Time: 4:03:29 PM
User: N/A
Computer: SERVER1
Description:
The following boot-start or system-start driver(s) failed to load:
IPSEC

However, according to Services, IPSEC is actually running.

It appears the errors occurred after I uninstalled the iSCSI Initiator, based on the System event log.

I checked a multitude of settings on the server (see winhlp.com/wxnet.htm). Everything appears to be correct. The Server is the master browser, all the required services are running, INCLUDING IPSEC, etc.