If you are using SQL Server management Studio much the we can observer that the list of server names in the log in of it. As you can imagin a period of time after 6 month or 1 year you will see a long list of server names in the login dialog.
How to clear this list...?
I doesn't provide a mechanism to clean nor clear the list, so you'll have to do a little browsing through your file system.
For SQl Server 2005 Management Studio, we should delete the below file
C:\Documents and Settings\<user>\Application Data\Microsoft\Microsoft SQL Server\90\Tools\Shell\mru.dat.
For SQl Server 2008 Management Studio, we should delete the below file
C:\Documents and Settings\<user>\Application Data\Microsoft\Microsoft SQL Server\90\Tools\Shell\SQLStudio.bin.
After deletion we can re-login the Management studio and can see the empty list.