1) Shut down your computer and power off the router for a couple of minutes. Restart computer
2) Right click on your network logo in the Notification Area - down by the clock (two blue monitor screens) select 'Diagnose and repair'
3) Use ccleaner to keep your browser(s) optimised
Download 'ccleaner' and use it daily. Run it through a couple of times,using the factory settings and the 'Analyze' control to see the files offered up for cleaning. Use 'Run Cleaner' to delete these files and then run 'Analyze' again to ensure all files are deleted
Run the 'Registry' from the left hand toolbar but 'Save' any changes after opting to 'repair' errors.
Never make changes to your Registry without saving the information.
4) Even if you have another browser set as default Messenger is coded with IE so make sure IE is up to date and not set to 'Work Offline' in 'Tools'. Use IE to check you have Flashplayer loaded.
You also need Java Runtime Environment. Visit the page and click on "Do I have Java?" under the "Download" button
5) Open IE > Tools > Internet Options > Connection (tab) > LAN settings - Uncheck everything except 'Automatically detect settings' > OK > OK
6) On the sign in page - click Messenger - click Internet Preference
Make sure the information in the 2 lower boxes is correct - if not use the drop-box arrows to display the correct information - click Apply and OK
7) If the info is correct toggle between 'Connect direct' and 'Use a Proxy' > Apply >OK
8) Select 'troubleshoot ' and 'show details' this can slow the software down long enough to sign in if the Yahoo software gets out of sequence
9) Run the sign in wizard