A Cisco 2612 router has some age on it. I remember the 2612 having integrated 10mb/s ethernet and token ring interfaces. This device does have some age on it.
If the hardware is sound, this could possibly be caused by terminal settings. I mention this because you said that you cleared the password. If you did this by booting the router and breaking into ROMMON mode, perhaps it is possible that another setting was changed for the baud rate of the console serial connection while you were also setting the router to boot without loading the startup configuration.
Eliminate this possibility or resolve the problem by rotating through baud rates in your terminal emulator and booting up your router. If this is the cause, one baud rate setting will allow the screen to be viewed.
The reason that I suggest this is that console port speeds can be set higher such as 57600. This would be great for sending an IOS image file over the console serial connection using XMODEM protocol in comparison to doing so at
9600 baud. If you console connect later at 9600 baud, the characters on the screen appear as gibberish. Set your baud rate to match, get the connection to be viewable, boot into ROMMON and set the baud rate back down to 9600, then load the IOS back up.
Refer to the documentation on Cisco's website for the specific hexadecimal setting for changing the baud rate for the console connection. Now that your password has been reset, if you are able to view the console, boot into ROMMON mode and enter the following: rommon 1 >confreg 0x2102