If you are having trouble installing drivers for your A50, follow this guide step by step.
Installing USB ADB Drivers or USB Debugging Drivers:
Open 'Device Manager'.
Right click on 'Micromax A50' and click 'Update Driver Software'.
On the new window, click 'Browse my computer for driver software', then click 'Let me pick from a list of device drivers on my computer'.
Click 'Have Disk'.
On the new Pop-up window, click 'Browse' and go to the folder where you previously unzipped the drivers and open the folder usb_driver.
Now select from the list of files 'android_winusb.inf' and click 'Open', then click 'OK'.
Now from the list of 3 options, select 'Android ADB Interface' and click 'Next'.
An 'Update Driver Warning' will appear, click 'Yes'.
Another Warning will appear asking 'Would you like to install this device software.
Now the drivers should be installed.