Problem with cell locking and protecting the sheet

Hi,

I am trying to lock cells in my excel worksheet and subsequently protecting the sheet with a password as i want all the formulae in the sheet to be non-editable to the users.

I have around 2000 data rows in my excel and when i choose to protect the sheet and enter the password, the excel becomes unresponsive. I have tried it many times but the problem continues.

Any idea why this would be happening? Is this because of the size of the data I have in the sheet? I tried it with the smaller data set and it works fine.

Thanks in advance for the help.

Regards,

Shantanu