Game keeps CTD when i try playing it, no error msg appear when i do crash.

On the other hand it seems to be working fine when i am not running any kind of dlc or mod.

What's your mod load order? Did you sort it with BOSS?

Just did a scan with BOSS says something about dirty edits and needs cleaning.

• Update.esm Active
  • Bash Tag suggestion(s): {{BASH: Delev, Relev}}
  • Contains dirty edits: 92 ITM, 3 UDR records. Needs http://skyrim.nexusmods.com/mods/25859 cleaning. A cleaning guide is available http://www.creationkit.com/TES5Edit_Cleaning_Guide_-_TES5Edit.
• Dawnguard.esm Active
  • Contains dirty edits: 619 ITM, 82 UDR records. Needs http://skyrim.nexusmods.com/mods/25859 cleaning. A cleaning guide is available http://www.creationkit.com/TES5Edit_Cleaning_Guide_-_TES5Edit.
  • Bash Tag suggestion(s): {{BASH: Delev, Relev}}
• HearthFires.esm Active
  • Contains dirty edits: 184 ITM, 11 UDR records. Needs http://skyrim.nexusmods.com/mods/25859 cleaning. A cleaning guide is available http://www.creationkit.com/TES5Edit_Cleaning_Guide_-_TES5Edit.
• Dragonborn.esm Active
  • Contains dirty edits: 61 ITM, 8 UDR records. Needs http://skyrim.nexusmods.com/mods/25859 cleaning. A cleaning guide is available http://www.creationkit.com/TES5Edit_Cleaning_Guide_-_TES5Edit.

And have you done it?

Dirty edits shouldn't be a problem if he has only official DLC.

So let me get this straight. Vanilla game works fine. You activate the DLC and it starts crashing. Strange, assuming no other mods are used. I'd try verifying file integrity on Steam in case something is missing.

When exactly does it crash? After loading a save or still in the main menu?

Managed to get that tessedit working just now, so gave it a go after that. now it seems to be working.

And it crashed earlyer just after the god-company-logo on startup.

Thanks Rosveen for the BOSS tips.

Crashing on logo is a indication that a mod is missing its master file.

Post the whole mod load order.