I got exactly the same issue. Any help please...
Currently running: Windows Vista Home Premium
Alright. So here's what's happened. Yesterday, I had used Windows Live Messenger, and it worked fine. This morning, I had used Windows Live Messenger, and it worked fine. But during the afternoon, it seems to have just completely stopped working. So first off (before I tell the errors), I tried running it in Admin mode, no luck. Changed compatibility mode for Windows XP SP2, and Windows 2000, still no luck. So then I restarted my computer, to see if that would work. Nope. Uninstalled Windows Live Messenger, reinstalled it with a freshly downloaded installer, still no luck. Now here's the thing, I haven't downloaded anything, installed anything, or visited any sketchy websites in between these times - there is nothing new on my laptop.
So here's what happens. I run Windows Live Messenger, and it gives me the following error: "Windows Live Messenger has stopped working. A problem caused the program to stop working correctly. Windows will close the program and notify you if a solution is available." Alright, cool. Let's debug it. So using the Just-in-Time debugged that comes with Visual Studio 2010 Professional, it debugs it, and tells me this:
"Unhandled exception at 0x72f32ee5 in msnmsgr.exe: 0xC0000005: Access violation reading location 0x00000018."
No clue what it means, but googling any of the above errors tells me nothing, there's no results.
So here's where I'm lost, I've tried all the standard ways of fixing a program, and I'm not sure how to proceed. So any idea's? :\