It would always be advisible to back up the control file before you start playing with that. Check the file permissions, check the initsid path of your control file and always shutdown the database before you start fiddling with the control file. At this point my suggestion would be the following. backdown to the original status and make sure that you are able to bring up the database. then do a clean shutdown. copy the control file to the appropriate locations. make the modifications in the initsid.ora file start up the database by first brining it on the nomount stage, then the mount stage then the recovery (if you have the archive mode on) and then open the database.
I hope this would solve ou the problem. In the mean time could you also post the alert log message.