3com 2916 reset

Use a brute force password solver or at best do a reset

I believe this website has the answer you need: (I know it says 3com but HP purchased 3com a few years back) http://www.edugeek.net/forums/wired-networks/97909-anyone-know-how-factory-reset-3com-2824-sfp-hp-v1910-24g.html

take it to the 4s garage, if you want to find out the problem by yourself,you first have some professional tool , there are some diagnostic that always can figure out the problem i can show you: www.xcardiag.com/

It will have a reset button on it, hold it down for ten seconds and it should reset the router to factory.

Manual can be found at the following web site:
http://support.3com.com/infodeli/tools/switches/baseline/3Com_Baseline-Switch-2916-2924_User-Guide.pdf

you can refer the user guide

http://support.3com.com/infodeli/tools/switches/baseline/3Com_Baseline-Switch-2916-2924_User-Guide.pdf

Open your browser and enter the 3Com URL configuration address
http://192.168.1.1
Then go to the Menu Screen and select Reset to Factory Defaults.
When to change the rouer's wireless settings then you will also need to apply these changes to your wireless card in the computer so it can connect to the 3Com router.

For 3com type of routers, you must connect firstly to 3com setup, By:
First: open your browser and type 192.168.1.1
Second: you will find adapter setting and reset it, it all depends upon your router's software.
Third: the easiest way is to reset it from the small button in the back of your router.

Just find the "reset" button that can be pressed by paperslip and this will reset router back to factory settings

page 22 of the 3com user guide for your switch talks about how to use the console cable and how to connect to your pc, I included the link below for your manual, if you don't have it:

http://support.3com.com/infodeli/tools/switches/baseline/3Com_Baseline-Switch-2916-2924_User-Guide.pdf