The cooker has it's own seperate cable and fuse.
The remaining socket outlets should be part of a ring main circuit, or maybe two ring main circuits if your property is large.
Your dodgy kettle should have blown the fuse like you thought,so
a. did you look at the correct fuse?
b. did you actually test the fuse?
c. Is the fuse 'over rated'?
I can only think an open circuit has occurred, but how and where?
I would remove all fuses except the one for the sockets and use a non contact tester to see if there is a live wire leaving the fuse box.
I would use the non contact tester at each socket outlet to see if there is any live wire present. don't forget the break could be in the neutral and the socket you plugged the kettle into may be the culprit.
You did not state if the kettle was found to be at fault.
As you know a socket on a ring main has two live wires fed to it and two neutrals unless it is on a spur off the ring circuit when it only has one of each.
I'm sure with a little logical testing you'll soon find the cause