Instead of looking for part14.rar in isolation, search for the complete set. The firmware is likely labeled as Micromax 50 Canvas 3 Stock Firmware (Flash File) .
To install this firmware via USB, you will need the SP Flash Tool and Micromax USB Drivers . Important Notes: Download MICROMAX L40CANVAS Firmware USB part14 rar
Based on search results, the firmware you are looking for appears to be related to the Micromax Canvas series (specifically potentially the L40Canvas-3/50Canvas-3 model). Instead of looking for part14