[69LM1]

Tell them to click start, run, type "CMD", press enter, type "IPCONFIG /FLUSHDNS" in the black box that appears, when they get the statement "successfuly flushed the DNS resolver cache", type "exit" and press enter.
Open IE and click on "Tools" and "internet options" and click on delete cookies, then click delete files (inc offline files) and click clear cache.
Then try.

Note: This will also clear out any stored passwords and user names cached in IE, so they will need to re enter them and login to Yenko.net again.