Restore DB fails

I created two named instances on my machine
SYED
DEVDB

Backed up AdventureWorks to C:Backup/bkp1

tried to restore onto DEVDB ????

It fails.. it says


 TITLE: Microsoft SQL Server Management Studio------------------------------Restore failed for Server 'ZAFAR-PC\DEVDB'. (Microsoft.SqlServer.SmoExtended)For help, click: http://go.microsoft.com/fwlink?ProdName=Microsoft+SQL+Server&ProdVer=10.0.2531.0+((Katmai_PCU_Main).090329-1045+)&EvtSrc=Microsoft.SqlServer.Management.Smo.ExceptionTemplates.FailedOperationExceptionText&EvtID=Restore+Server&LinkId=20476------------------------------ADDITIONAL INFORMATION:System.Data.SqlClient.SqlError: The operating system returned the error '32(The process cannot access the file because it is being used by another process.)' while attempting 'RestoreContainer::ValidateTargetForCreation' on 'C:\Program Files\Microsoft SQL Server\MSSQL10.MSSQLSERVER2\MSSQL\DATA\AdventureWorks.mdf'. (Microsoft.SqlServer.Smo)For help, click: http://go.microsoft.com/fwlink?ProdName=Microsoft+SQL+Server&ProdVer=10.0.2531.0+((Katmai_PCU_Main).090329-1045+)&LinkId=20476------------------------------BUTTONS:OK------------------------------ - did not match any documents.


After several tries I tried the following

1. Disconnected the first Instance completely... NO USE
2. Restarted SSMS............................................. NO USE

just now while I am typing this question in EE i tried again..
very carelessly ..so i gave DB name as 1234

...and it worked..

So When i restore DB on to another Instance do i have to change the DB name ?

My SS Config Manager Screen shot is attached

Please Help
error1.PNG