Double-clicking on SkyrimLauncher.exe and TESV.exe causes the Windows pointer to act like it is starting a program, but nothing happens. Same when trying to start Skyrim through Steam. No Skyrim related applications show up as running in the Task Manager.

Disabled all mods; no go

Disabled all background programs and services; no go

Uninstalled/Reinstalled Skyrim; no go

Uninstalled, deleted all remaining files(except for save folder) in both SteamApps/Common/Skyrim and in MyGames/Skyrim, then reinstalled; no go

System Specs

OS: Windows 7

Processor: Intel i5-2500k

RAM: 16GB DDR3

Video: 2x Nvidia 560ti in SLI

Sound: Creative X-Fi Titanium HD

Storage: Crucial M4 128GB SSD

I've been running Skyrim on this system since Skyrim came out. Anyone know what might have caused this sort of problem?

Sounds like something is blocking it but it is slow to let you know. Did you try disabling any AV you have?

Just double checked to be sure. No antivirus running

Any installations (applications, drivers, etc) since the last time you played?

What about UAC? I know you said you have played since release but UAC tends to have a mind of its own.

Driver: no. Programs: plenty, but all games, and all installed to a different hard drive.

UAC is off.

This could be a long process, but the first thing I'd try is uninstalling/reinstalling my audio and graphics drivers. Make sure you have nVidia's latest (320.49).

BAM! Windows Event Viewer + Google = Success!

Turns out it was a Steam problem. Had to remove a file called ClientRegistry.blob from the main Steam folder. Restarted Steam, and I'm back in business.

Where "in business" is defined as spending the rest of the night reinstalling all my mods. Oh well. At least the problem's fixed.

Well done. I can't count the number of times I've tried that without getting anywhere. Shows I shouldn't give up hope.