Another tale from the trenches .. that being my own personal experience on my PC! Windows Live Messenger refusing to sign in, giving an 8100030d error. Most suggestions include regsrv32 commands to reregister dll files, resetting modems etc, nothing which worked on Vista for me. Until I remembered that Tony had recently upgraded my software to AVG Anti-Malware SBS Edition version 8.0.87. So, diabled the Resident Shield – no go. Went into the Web Shield and unticked the Instant Messaging, MSN Protection – still no go. Disabled the Web Shield entirely and what do you know …. hello, messenger, you have returned! Yuck – I’m now off to report this to AVG.