<<< trouble is no info with s/hand modem/router(wired) >>>
There should be a button (recessed?) at the back with which you can "hard reset" the router back to factory default settings. You should then be able to access its Setup pages by entering 192.168.1.1 into a web browser. You will be prompted for a Username & Password. Linksys routers normally have no Username (leave blank) and a Password of "admin"
If you cannot access the Setup pages, try giving the Local Area Connection in your PC a fixed IP address in the same Subnet as the router, for example 192.168.1.2 with Subnet Mask 255.255.255.0