Slow logins in Windows 7

According to Microsoft the welcome screen may be displayed for 30 seconds during the logon process after you set a solid color as the desktop background in Windows 7 or in Windows Server 2008 R2
To fix this configure the value of the DelayedDesktopSwitchTimeout registry entry. This value determines the time-out interval of a session before Windows 7 or Windows Server 2008 R2 switches between sessions.
To configure the value of the DelayedDesktopSwitchTimeout registry entry, follow these steps:
Locate the following registry subkey:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\SystemDouble-click the DelayedDesktopSwitchTimeout registry entry.
In the Value data box, type 5, and then click OK.
On the File menu, click Exit.