What "failure" did you incur?  Did you have to restore an entire hard drive?  Did you have to reinstall all the system software?  Are your data and image files on the same directories and drive locations as before?  Are their changes in drive letters or addresses?

The Studio program files will be at the default Windows location for all program files, unless you designate differently when installing a program.  By default, Studio will also save project and AUX files to a standard location on the C drive, unless you pick other locations.  Very often, one does pick a special location or external drive directory, for such purposes, if creating many HD projects or if one needs lots of space to export AVI files from standard definition projects.

If you move around video or other source media files for a project, Studio will not be able to find them unless you can point it to the new location(s) and the sub-directory structures and file names remain the same.

Normally, Studio should be able to regenerate thumbnail or other incidental temp or aux files associated with a project.  It will re-create them at a C drive location, unless you manually designate a special location.

If you always let Studio pick the project file locations, and gave your projects unique names, or if they had discrete dates, they are probably all on one of the user documents folders or directories of your C drive, or you may be able to find them by using a Windows Explorer search.

A rudimentary search for "stx" will find the "pointer" files to open old projects.  The stx files contain nothing else themselves, but tell Studio where to look for the other project files.  If this does not work, then your file locations may have been erradicated or altered, leaving you with the choice between manual search or starting over.  If you must chose the latter, I recommend experimenting with manual designation of project file or output destination, so that you might be able to quarentine or fix trouble the next time your system suffers near-death.