Behseini -2 Junior Poster

Hi Guys,
I am using SQL Server 2008 R2 on Windows Server 2008 Standard Edition.I tried to uninstall one of instances in SQL Server and I believe I "Select all the features" to remove from the Select the features windows.After uninstalling, I tried to run SQL server with another existing instances which I noticed the SSMS also has been removed!
Now my question are:
1- How Can I add the SSMS to other instances again?
2- why did I lose the SSMS for all other instances while I was uninstalling just one of them(Instances)?

Thanks,