Can someone hack my router and change my admin password for Linksys router but leave my wifi passwords the same. Tried logging in on 3 different browser and 2 different computers. I also tried using the general admin password when initially setting it up in case it failed during an electrical surge. Not such why I couldn't log in to my router. Could it have been hacked?
Yes it could be hacked especially if password was not strong enough or simply because of vulnerable router.
Make sure that firmware is up-to-date, then check logs if it has one and change password to something decent.
Here it is how to reset a password:
Resetting the Linksys router to factory defaults
If you can't access the router's web-based setup page or forgot the router's password, you may reset the router to its default factory settings. To do this, press and hold the Reset button for 10 seconds.
NOTE: Resetting your router to its default factory settings will also reset your router's password. The router's default password is “admin” as for the username, just leave the field blank.
IMPORTANT: Make sure that the Power LED of the router is blinking when you press the Reset button. This indicates that the router is being reset properly.
NOTE: The location of the Reset button may vary for every model. Older Linksys devices may require pressing and holding the Reset button for 30 seconds to complete the reset process.
Yes, if someone had access or guessed your router password they can/could change your router admin password and leave the wifi password the same, the attacker already knows the wifi password btw, needless to change that. However a quit reset should solve your problem. And it is good to have admin and wifi secure passwords.