Restart from DVD does not work

I wanted to reinstall my system from scratch to solve a number of problems that I had and I made a crazy thing.

I put the system/library in the bin with the idea to restart and reinstall all the system from my original DVD.

But it does not work.

The computer does jnot start by itself and does not start from the DVD. I tried several options: holding C, D, X space keys but no results.

The computer scree, screens remains white with alternatively ? and apple logo but nothing more.

What can I do ?

Thanks

Marc