You could use M-files for file management. There is an express version that is free and gives full versioning and vault (check in/out) capabilities but is limited to 1000 files (I think).
http://www.m-files.com/eng/express_free.asp
Windows 7 x64, Precision T3400, Intel C2Q @ 3 GHz
8 GB RAM, ATi Radeon HD 3870 |