Thanks for your help. I tried a different computer and browser but still no luck.
I need to fill you in on my attempts to recover the password for my switch:
1) First off, my ISP is Rogers.com and the default IP address of my modem is 10.0.0.1.
2) Prior to contacting this forum, I was able reach my switch at IP address 10.90.90.90. However, when I put in the default credentials, it failed. I did a factory reset by pressing and holding the reset button until the 16 LED lights flashed amber and then green. I did this several times and kept trying the following combinations: admin/<empty>, admin/admin, and admin/password. However, they all failed.
3) One of the times, I was prompted to upgrade the firmware.Thinking that loading new firmware might reset to the default username and password, I found an upgrade and loaded it. I found this file DGS-1100-SERIES_REVB_FIRMWARE_v1.01B053_HOTFIX.zip on the USA D-Link tech support website and loaded it. Once again though, I was unable to login.
4) During my research I found this forum and posted my question. However, prior to your answer, last night I connected with D-Link tech support via web-chat.
3) The D-Link agent on the web-chat said that the two devices needed to have the same IP address values for the first 3 portions of the IP address (e.g. 10.0.0.X, or 10.90.90.X).
4) During the web-chat, I completely disconnected my switch and laptop from my home network. (I was still connected to the internet and web-chat via WiFi.) I connected the laptop directly to the switch. I set my laptop Ethernet adapter to 10.90.90.43 to match the switch at 10.90.90.90. I was able to bring up the switch login screen. However, I was unable to login. At the agent's request, I tried all three username/password combinations above and they all failed.
5) At the agent's request, I pushed the reset button on the switch and held it for 1 minute. I then tried to login but once again the 3 combinations all failed.
6) The web-chat ended with the agent going off to investigate the hotfix firmware to confirm that it wasn't causing additional problems. I haven't heard back yet but, hey, it's a holiday weekend.I'm sure I'll hear when there is news.
7) I signed off the web-chat saying that I would reconnect my laptop and my switch to my network and set up a static IP for the switch in the 10.0.0.X range. I used the modem console app at 10.0.0.1 to configure the switch to be at 10.0.0.90. What's odd is that the modem console shows that static IP entry as being disconnected, even though it is physically connected. (And other devices downstream from the switch are recognized as connected via Ethernet.) When I try to reach the switch at 10.0.0.90 from my Chrome browser, I get a time-out error. What's worse is that the modem console app doesn't appear to have a means of removing the static IP assignment. I guess I'll do a factory reset the modem to clear that issue (hopefully).
Sorry for being long-winded but thought you might as well have the all story to this point, just in case it helps. Actually, there is one more point. When the switch was first installed, it was done by my son. I take it as self-evident that he changed the password, since the default no longer works. However, he doesn't recall the new value.
At this point, I've got 2 questions for you, please. First, I'd like to confirm if the modem and switch need to be in the same address space for first 3 portions of the IP address. I'm asking because previously when they were each using their default IP addresses (10.0.0.1 for the modem and 10.90.90.90 for the switch) I was able to bring up the switch login page.
Second, now that you've got the back-story, can you suggest next steps to recover the switch admin password?
Thanks again, Barry