If you really mean to "unprotect the VBA project" you need to enter the password.
Do you actually mean you want to avoid the message about the VBA when you start the database?
Obviously this cannot be done with any kind of code such as SendKeys because the code is disabled. Moreover, having code to disable the code warning would render the whole idea of protection against code pointless.
One solution is to completely turn off the warnings by changing the settings on the computer. This is not a good idea because it will then run all code without warnings.
The best way in 2003 is to digitally sign the project so the user only needs to answer the question the first time. For 2007 the database can be placed in a Trusted Location.