None of the guards will tell me about dawnguard and when I go there the npcs won't talk to me its frozen even the plastic surgeon in riften won't talk to me I have tried re-downloading the DLC but it hasn't change can anyone help force start the questline or something?

What level are you? You need to reach level 10 before hearing rumours of Dawnguard re-forming.

It doesn't matter what level you are, and you don't need to hear any rumors in order to get the quest started. You can be fresh out of Helgen and only at level 1. Simply head directly to Dayspring Canyon. The quest will begin once you enter the canyon and interact with Agmaer (the rookie NPC seeking to join the Dawnguard).


EDIT:

Sorry, I didn't read this bit carefully enough:

"...when I go there the npcs won't talk to me its frozen..."

By "there", do you mean Dayspring Canyon?

EDIT: You know what, I'll just erase all this nonsense.

Stupid question, I know, but have you tried restarting the game since installing it?

Like turn the system off, turn it on, start the game, and go from there?