To clarify, I think you are saying that you use your Windows Live Mail (WLM) client on your PC to access your BTYahoo email a/c whenever you have trouble logging into this email a/c using Webmail.
There is no connection between logging using POP3 or IMAP that WLM uses and logging in online on the Web, particularly as with WLM you have the advantage that your login credentials are stored so you don't need to type them every time.
Why only use WLM "in reserve as emergency" anyway? It is a far cleaner, faster and more reliable method for accessing your email a/c's than webmail.
Even ancient users will prefer email clients like WLM in preference to webmail, particularly as the webmail access is relatively recent; in the beginning there were only email clients
1999: Freeserve 48K Dial-Up => 2005: Wanadoo 1 Meg BB => 2007: Orange 2 Meg BB => 2008: Orange 8 Meg LLU => 2010: Orange 16 Meg LLU => 2011: Orange 20 Meg WBC