Question : can not manage computers in management tool

Dear all,
Recently, I've got an error message when I try to connect to computer X in
the Computer Management too; "computer \\X cannot be managed. The network path was not found."
the computer is running fine, domain users can log on, I can ping
it, and I can connect to its screen via remote desktop.
Before it was running fine, I mean I can managed all computer in computer management tool, but after I replaced a core cisco switch 6509, it had problem like that.
 
I really appreciate for all your comments.
Please help
danny

Answer : can not manage computers in management tool

PAQed with points refunded (200)

Computer101
EE Admin