Need to reconfigure but have no disc
After a power outage, lost WIFI connection. Spent time with cable supplier and Linksys on phone ( they say router is too old - but it is only 2 years old). Apparently need to re-configure, but can't find original disc. I think it should be simple procedure but all tecky people I have talked to so far want me to buy a new router. I think this one should still be ok. Please help. Thank you.
Model: Linksys EA3500 smart router ( N750)