Hi,
Cass' solution should solve the problem .... but only if the deleted file was included in the 'System Restore' back-up ....
Shouldn't it work ... (talking of personal experience here ...

) ...
1* reinstall Photoshop, (if you do this, remember to save first your personalized Photoshop settings ... usually, the whole 'Presets' Folder found in
C:\Program Files\Adobe\Adobe Photoshop XX and the 'Photoshop' Folder found in
C:\Documents and Settings\Your Name\Application Data\Adobe .... otherwise you'll be brought back to the initial Photoshop default settings .... )
2* since restoring files or folders from the recycle bin is never like installing them .... you could try a new install of the program/s you deleted and, if this works, delete them again but choosing to keep the files that might be 'used' by other programs during deletion....
Hope this helps ...