Clear Drop Down List of Recent Connection From SQL Server Management Studio

Delete mru.dat file in xp-os in Windows7 Delete  SqlStudio.bin

 Sql 2005
C:\Documents and Settings\\Application Data\Microsoft\Microsoft SQL Server\90\Tools\Shell\mru.dat
If you can not find mru.dat at above location look for mru.dat in following folder.
C:\Documents and Settings\[user]\Application Data\Microsoft\Microsoft SQL Server\90\Tools\ShellSEM\mru.dat
For SQL Server 2008:
C:\Documents and Settings\\Application Data\Microsoft\Microsoft SQL Server\100\Tools\Shell\mru.dat
If you can not find mru.dat at above location look for mru.dat in following folder.
C:\Documents and Settings\[user]\Application Data\Microsoft\Microsoft SQL Server\100\Tools\ShellSEM\mru.dat
 For SQL Server 2008 R2:
in Windows7 Delete  SqlStudio.bin  file from location
  C:\Users\[user]\AppData\Roaming\Microsoft\Microsoft SQL Server\100\Tools\Shell\