BleepingComputer.com: Windows Live Mail won't start

Windows 7 with sp1. and all other patches (except one for PPT 2007 which is no longer in use since upgrade to 2010)

Windows Live Mail used to work fine, send and receive emails etc.
Now when I click on the icon in the taskbar, or in c:\program files\Windows Live\Mail\wlmail.exe I get a Windows wait icon (spinning blue circle) for a few seconds and then nothing. This is the same directly after a reboot or after trying several times. wlmail.exe is NOT in the task manager list of current processes.

No splash screen. No error messages. Nothing obvious in event log.
Repaired application and no change.
Rolled back most recent Windows updates and no change. Reinstalled updates, installed Live Mail 2011 which updated app to latest version and no change.
Tried a clean boot with no startup apps and no non-MS services, no difference.
Logged on as admin account (usually run as non-admin user with UAC on), no difference (so looks like it is not related to user or profile etc).

In <user>\AppData\Local\Microsoft\Windows Live Mail is a file WindowsLiveMail.log which shows paired entries for each attempt to start the app such as:
Log opened 2011-04-23T16:15:40Z
Windows Live Mail 15.4.3508.1109
***
***
Log closed (normally) at 2011--4-23T16:15:45

So something is happening, something is getting logged but nothing to show why the application does not open.

After clicking, Task manager shows both wlmail.exe and then wlstartup.exe brirefly, but these both disappear with nothing visible having happened.

Any idea what is happening?
What can be done to fix it?
What can I do to ensure data is backed up (where are all the emails and contacts stored?) before doing more drastic things such as uninstalling and reinstalling the application?

All help very gratefully appreciated

Quote

Nothing only praying that it will work soon.
Why say I that? Well, also got you not a mention, but they have a problem with their program.
I use at this moment Xp and I can also not working fine with that.
When I try via messenger or via their site, visit my hotmail, than get I also problems and the other time, the same what you have.
So what I can say is, be patient.

Hi AdamV,
I have had this same problem with Windows Live Mail, and it is the main reason why I use Thunderbird now. It seems to be some sort of bug. When this happens, check in the Task Manager if wlmail.exe (off-hand, didn't check the name of the process) is still running. If so, end it, then try again to start Windows Live Mail.

I had this bug on XP, have spend a lot of time searching for a solution and found... none.