What device are you using to access your emails?
How are you accessing your emails, is it using webmail via a web browser or via an email client/app.
Are you on the BTYahoo or BTMail system. If you are not sure log onto your email via a web browser and if you see Yahoo anywhere you are on the BTYahoo system.
I am on BT Yahoo everything is working on my iphone and if I use another laptop - it is as if the psge is locked or frozen
You never answered the question about what device and how you access your email. Presumably by your reply you are having problems with a laptop and again presumably via a web browser, is that correct?
I assume you are using a web browser.
If your email is working as it should on all other devices/computers it would appear that it is a problem with either your PC or the web browser you are using.
The first thing to try is to re-start your PC. If that doesn't help you should try clearing the cache/cookies etc from your browser. To find out how to do that Google "clearing cache" for which ever browser you are using.
If that doesn't help try downloading another browser such as Chrome or Firefox and see if it works.