Need to reinstall win 8.1 after a disk crash

After a crash I need tot reinstall win 8.1. With my XPS 8500 there was no disk delivered.

If I want to download pre-installed software from the support web-site from Dell, it seems there is nothing happening.

On my Dell there is also a sort of OEM product-key so I can't use any other install disk... 

What can I do? Thanks for an answer.