Just got a blue screen, first ever with Win7 64, restarted, started CK, began to load my world, and it as gone. Nothing, just 1 cell that says Wilderness, like as if I was starting a new world. Interior cells are there but when I click on a teleport marker to get outside CK crashes. Have verified files. The esp file is still in the data folder as is the bsa.

HEEEEELLLPPP!!!

You'll find a backup of your mod in the "Backup" folder in the Skyrim main folder. Inside you'll find the last version of your mod.

Steam\steamapps\common\skyrim and in the backup folder you should have some backed up files. Change bak into esp and it'll turn into a plugin file.

Ninja'd like a baws.

If anything, see this as a wakeup call. As somebody who has worked on two multi-year projects thus far, you learn pretty quickly that it's always a good idea to create backups of your own, especially off-site backups through something like Dropbox.

Thanks guys. I've used the backup folder before, but the last time I used a backup it had the name of my mod. This time there was no .bak file with my mod's name. Fortunately I have autosave running in CK so I reckon I've lose 10-15 minutes of work. I do upload to Skydrive about every couple of weeks, thankfully I haven't lost weeks of work.

All sorted now, I'll just untie this noose, thanks all.

In a similar vein I loaded up a dungeon recently I'd poured hours into, only to find the cave system at the beginning was all I could see. Let's just say I [censored] my pants... and then realised if I pan the camera slightly to the right I'll see the rest of it

OT: Good to hear you didn't lose too much work. Always keep backups!!! I even backup fully once every few weeks onto a flash drive in the event my PC kicks the bucket.