Back up all data before you do anything else.
NEVER RESET THE KEYCHAIN unless you want to destroy its contents.
This operation might cause your keychain to be deleted again, so be prepared for that. You have backups.
Launch the Keychain Access application.
Select the login keychain from the list on the left side of the Keychain Access window.
If the lock icon in the top left corner of the window shows that the keychain is locked, click to unlock it. You'll be prompted for the keychain password, which is the same as your login password, unless you've changed it.
Right-click or control-click the login entry in the list. From the menu that pops up, select Change Settings for Keychain "login". In the sheet that opens, uncheck both boxes, if not already unchecked.
From the menu bar, select Keychain Access ▹ Preferences ▹ First Aid. If the box labeled Keep login keychain unlocked is not checked, check it.
Select Keychain Access ▹ Keychain First Aid from the menu bar and repair the keychain. Test.