First: Create a drive image of your C: drive NOW. Use a USB loaded distribution like SLAX to back this image up to an external hard drive, for example. This will assist any data recovery operations later. The more you use the drive now, the smaller the chance becomes that you can recover ANYTHING.
Next: Try TestDisk, and its program PhotoRec, which searches for various files (images, plain text, word docs, zips) by looking at file headers. Run from within a new folder on a drive with a lot of free space. Point PhotoRec at your image file, and recover files to the new folder. It will create several recovery directories, which may contain anything from your work files to garbage from your Web browser cache.
Then: Wait. Or run in the background.
If you hadn't formatted the C: drive, the TestDisk program from the testdisk suite has an undelete option, which does reasonably well at recovering recently deleted files from NTFS, and FAT32 drives, at least.