Search for files with a specific file extension in Windows 7 [duplicate]
Windows Vista and higher support the Advanced Query Syntax (AQS). To search for files with a particular file extension (.doc), you'd type:
ext:.doc
or simply:
*.doc
(the 1st one is better - it's well worth learning AQS)
To find exact matches, enclose the extension in double quotes:
ext: ".cs"
AQS References
Advanced Query Syntax (Windows)
Mastering Windows Search using Advanced Query Syntax | Ars Technica
Exploring Vista's Advanced Search
How to Search for Files Created Between Two Dates in Windows