prblm to start after parameter change

Hi All,

I have changed some parameters, for which i have to take restart.

when i restarted sever , its giving message as " Instance on host MDECCSAN started" gettting started but unable to login from GUI.

i have checked the profiles and restored the instance profile which has been changed to .bak, renamed it and tried again, but still the same problem.

Kindly suggest waht could be the reason.

Rgds!!