I'd suggest clearing cookies & saved passwords for the log in problem - on Internet Explorer it's Tools > Internet Options then on the first screen Delete button in middle then clear the top checkbox (Preserve Favourites websites data) tick the rest then Delete button at bottom. As for adverts maybe the laptop is running a different browser (Chrome, Firefox, etc.) with an advert remover built in or added-on? Possibly worth downloading & running a full scan with the free Malwarebytes malware remover to be sure there's nothing infecting the machine.
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