I get intermittentand failing connection to the internet and am advised to try different router settings to improve the connection. I am supposed to get a login box when entering 192.168.0.1 in the address bar but this does not come up.Where is the login box please?

Try 192.168 1.1 instead.
What make of router do you have ?

Sky

Have you had a read through Sky's help pages: Sky Broadband | Network connection settings