D-Link discontinued the DI-524 Wireless Router on February 01, 2008, in the U.S.
Most D-Link routers don't need a password by default, and that's true for the DI-524 router, too. When logging in to your DI-524, just leave the password field blank.
Other Login Info
The D-Link DI-524 does have a default username: admin.
The default IP address for the D-Link DI-524 is 192.168.0.1. This is the address that networked computers connect to; it's also the IP address you should use as a URL to access the DI-524 through a web browser.
The DI-524 router comes in four different hardware versions: A, C, D, and E. Each uses the exact same default password and IP address, and none require a username.
If the DI-524 Default Password Doesn't Work
If the blank default password for your DI-524 router isn't working, you (or someone else with access) most likely changed it since it was first installed (which is good). The bad thing about changing the password to anything other than a blank one, of course, is that it's easier to forget.
The solution is easy: Just reset the router to its factory default settings. This restores the password to the blank default, and the username to admin.
Restoring the router back to factory default settings will not only remove a custom username and password but also any other changes you've made, like the Wi-Fi password, custom DNS settings, etc. Make sure you record those settings somewhere or make a backup of all these settings (skip down past these instructions to see how to do that).
Here's how to reset the D-Link DI-524 router. The procedure is the same for all four versions.
Turn the router around so you can see the back, where the antenna, network cable, and power cable are plugged in.
Make sure the power cable is firmly attached.
With something small and sharp like a paperclip or pin, hold down the button inside the Reset hole for 10 seconds.
The reset hole should be on the far right side of the router, next to the power cable.
Wait 30 seconds for the DI-524 router to finish resetting, and then unplug the power cable for a few seconds.
Reattach the power cable, and wait another 30 seconds or so for the router to fully boot back up.
In a browser, go to http://192.168.0.1. Log in to the router with the default admin password from above.
Now is a good time to change the router's default password, because a blank password is not secure. Cnsider changing the username to something other than admin, as well. Use a free password manager to store this information so you don't forget it again.
Reenter any custom settings that you want back but were lost during the restoration process. If you made a backup, use the DI-524's Tools > System menu to find the Load button to apply the configuration file. If you want to make a new backup, use the Save button on the same page.
If You Can't Access Your DI-524 Router
If you can't reach the DI-524 router through the default 192.168.0.1 IP address, it probably was changed at some point. Fortunately, unlike with the password, you don't have to restore the entire router just to find out the IP address.
You can use any computer that's connected to the router to find the router's IP address. This is called the default gateway. See how to find the default gateway IP Address if you need help doing this in Windows.