So I broke dawnguard and don't know how to fix it.

When I finish the awakening quest, the bloodlines quest doesn't start. I have looked online and the only fix it seems is to start a new game, the only problem is that j did start a completely new game uninstalled all of my mods, reinstalled the mods I wanted created a new person, and luckily I just tested it first before actually getting into playing, but it's still broken.

Specifically what happens is that I complete Serena's dialog, but then the quest doesn't start. She just stands their and nothing happens. And on my last play though I had a bunch of mods, but the only mod I can think of that would affect Serena or the dawnguard quest that is currently installed is the bvfe serana and family mod and I have done dawnguard with that mod installed before.

Did you install some mods in a new game then uninstall a mod or two and then reinstall other mods?

I quit my last game when dawnguard stopped working. Completly reworked my mod list, leaving out anything that I thought could be causing the problem. Then tested a new game and dawnguard still didn't work.

Instead of guessing as to which mod might be conflicting, use tes edit. It will flat out tell you if there are conflicts. If that comes out with no issues, then verify game cache, because something really bad happened somewhere.

I dont really know how to use tes 5 edit. I know how to use it to find a missing master, but that's about it. Is there a tutorial somewhere I could read?

I see. Well the only thing I can say is to reinstall Skyrim from scratch, so all DLC are downloaded from Steam and doing that also assure you that Skyrim is updated.

Also make sure to read http://www.gamesas.com/topic/1425445-relz-tes5edit-plugin-cleaning-emporium/ thread about mod cleaning and ask questions about how to use http://www.gamesas.com/topic/1511975-relz-tes5edit/, but don't forget to read http://www.theassimilationlab.com/forums/topic/14507-guide-manual-cleaning-skyrim-master-files/ excellent guide for cleaning Skyrim master files and I recommend only do that if you know what you're doing.

Just a thought on this, but I encountered a similar problem when DG was first released. Turned out that I had a companion, so her stuff wouldn't fire properly and she just kind of stood there. My current solution is to either not bring one at all or to go back to the previous area and dismiss my companion before trying to wake her up. Mods like UFO or AFT don't really do anything that will fix that and might even compound the problem. Not sure if this was addressed in the unofficial patch, but it's just one of those things that I keep in the back of my head when I'm starting that DLC.

http://afkmods.iguanadons.net/Unofficial%20Dawnguard%20Patch%20Version%20History.html

I never had a follower while testing so it can't be this.

I just disabled every mod and tested to see if it worked, and it did so it must be a mod.

I figured it out!

it was either "Snow elf race - The true falmer" or the racial compatability patch that it needed.

I dont know why but for some reason that cause the problem, i might have to find a new falmer mod.