Not exactly a fix, however...
If you would like to revert to the classic NT/2000 logon scheme, this may be a work-around:
Open User Accounts in Control Panel
Click Change the way users logon.....
Un-check the Welcome Screen Option and
click the Apply Changes Button and try it out.
As an aside:
With Fast User Switching enabled, you can switch users while
still logged on by using the Windows Key (little flag on it by the CTL key)
and tapping the L key at the same time.
Good Luck!