Yahoo Messenger Keeps disconnecting

I'm having a bit of a problem with Yahoo Messenger, it keeps disconnecting and reconnecting (because I've got it set to connect automatically).
I've done a few web searches, and tried the various remedies proposed by various unknowns without success so I thought I'd drop the quandary upon your enlightened minds.
I've run "ping -t www.yahoo.com" it's not the connection. I've also had process explorer running waiting for the disconnection which happens every 10 - 20 minutes or so for any activity before hand but there is nothing apparent happening. It seems to be ok when run as an admin or from an admin account but not from my usual limited user account.
So there it is, any suggestions gratefully received.

Much Thanks.