No new mods installed prior to this behavior change. I cleaned it up with TES5Edit (exactly as instructed), verified Steam files, and installed every unofficial patch.
My game is not heavily modded, but it would be a pain in the ass to start over. There is no error message, nothing, just a CTD no matter what save I load. It was acting fine for hours and hours.
DxDiag info:
System Information
------------------
Time of this report: 11/30/2013, 22:55:45
Machine name: HTPC
Operating System: Windows 7 Professional 64-bit (6.1, Build 7601) Service Pack 1 (7601.win7sp1_gdr.130828-1532)
Language: English (Regional Setting: English)
System Manufacturer: Hewlett-Packard
System Model: HP Compaq dc7800p Convertible Minitower
BIOS: Default System BIOS
Processor: Intel® Core2 Duo CPU E6550 @ 2.33GHz (2 CPUs), ~2.3GHz
Memory: 4096MB RAM
Available OS Memory: 4016MB RAM
Page File: 2501MB used, 5527MB available
Windows Dir: C:\Windows
DirectX Version: DirectX 11
DX Setup Parameters: Not found
User DPI Setting: Using System DPI
System DPI Setting: 96 DPI (100 percent)
DWM DPI Scaling: Disabled
DxDiag Version: 6.01.7601.17514 64bit Unicode
------------
DxDiag Notes
------------
Display Tab 1: No problems found.
Sound Tab 1: No problems found.
Sound Tab 2: The file cmudaxp.sys is not digitally signed, which means that it has not been tested by Microsoft's Windows Hardware Quality Labs (WHQL). You may be able to get a WHQL logo'd driver from the hardware manufacturer.
Sound Tab 3: The file cmudaxp.sys is not digitally signed, which means that it has not been tested by Microsoft's Windows Hardware Quality Labs (WHQL). You may be able to get a WHQL logo'd driver from the hardware manufacturer.
Input Tab: No problems found.
--------------------
DirectX Debug Levels
--------------------
Direct3D: 0/4 (retail)
DirectDraw: 0/4 (retail)
DirectInput: 0/5 (retail)
DirectMusic: 0/5 (retail)
DirectPlay: 0/9 (retail)
DirectSound: 0/5 (retail)
DirectShow: 0/6 (retail)
---------------
Display Devices
---------------
Card name: NVIDIA GeForce GTX 650
Manufacturer: NVIDIA
Chip type: GeForce GTX 650
DAC type: Integrated RAMDAC
Device Key: Enum\PCI\VEN_10DE&DEV_0FC6&SUBSYS_26503842&REV_A1
Display Memory: 2723 MB
Dedicated Memory: 971 MB
Shared Memory: 1751 MB
Current Mode: 1920 x 1080 (32 bit) (60Hz)
Monitor Name: Generic PnP Monitor
Monitor Model: VOJ320F1A
Monitor Id: VIZ0061
Native Mode: 1920 x 1080(p) (60.000Hz)
Output Type: HDMI
Driver Name: nvd3dumx.dll,nvwgf2umx.dll,nvwgf2umx.dll,nvd3dum,nvwgf2um,nvwgf2um
Driver File Version: 9.18.0013.3182 (English)
Driver Version: 9.18.13.3182
DDI Version: 11
Driver Model: WDDM 1.1
Driver Attributes: Final Retail
Driver Date/Size: 11/14/2013 05:55:24, 18208624 bytes
WHQL Logo'd: Yes
WHQL Date Stamp:
Device Identifier: {D7B71E3E-4C86-11CF-9C57-5D061CC2C435}
Vendor ID: 0x10DE
Device ID: 0x0FC6
SubSys ID: 0x26503842
Revision ID: 0x00A1
Driver Strong Name: oem17.inf:NVIDIA_SetA_Devices.NTamd64.6.1:Section090:9.18.13.3182:pci\ven_10de&dev_0fc6
Rank Of Driver: 00E02001
Video Accel: ModeMPEG2_A ModeMPEG2_C ModeVC1_C ModeWMV9_C