My game started having this weird issue lately in which I can't seem to stay in first person point of view. The mouse wheel and 'F' will put me in first person, but almost immediately the game will revert to third person. Anyone else have this problem? Hopefully there's a fix for that. A number of weird problems started cropping up after installing Dawnguard, though I don't know if that's to blame, or some new incompatibility between that and pre-existing mods. The other thing that started happening after installing Dawnguard I noticed is the game often getting stuck when trying to load the exterior world when leaving a building.

Anyhow, help?

Hmmm, definitely Dawnguard. Disabling it allows me to stay in FP POV.