You are likely in a condition that is refereed to as "bricked". Most linksys routers have a firmware recovery option that allows you to use a TFTP server that it will attempt to load a firmware image immediately after a reset. They also have their own firmware. You will find a lot of information if you search for your router and the keyword bricked or firmware recovery.
At least you do not have to solder things into the router like you do on some.