Backup Problem

My PM given me a file as backup for MS SQL SERVER 2000 I want to restore it in MS SQL SERVER 2005
I can't understand what type of file is it I always use .bkp file in MS SQL 2005 please help me to
under stand
file is as attachmentno one is going to download and unzip your file because they are afraid it might wbe a virus. What is the file extension of the file inside the zip file?|||no one is going to download and unzip your file because they are afraid it might wbe a virus.From unzipping?

ankur, I don't see that your file has any extension on it. But the extension is superfluous anyway. Just rename it with a .bak extension and try restoring it to 2005. If it is a valid SQL Backup the 2005 should be able to restore it regardless of what extension is on it.|||From unzipping?

ankur, I don't see that your file has any extension on it. But the extension is superfluous anyway. Just rename it with a .bak extension and try restoring it to 2005. If it is a valid SQL Backup the 2005 should be able to restore it regardless of what extension is on it.

This is backup file for SQL SERVER 2000 in that when we take backup no extension come out I restored this file in sql server 2000 successfully
but problem occur when I try to restore in sql server 2005|||What problem?
Did you gen an error message?