Device listing in adb but not in fastboot

I faced this problem while rooting my Yuphoria.
First my device was not listing in ADB also.
After that I installed PdaNet+ on my windows laptop.
It will install all device driver for you.
After it, authorize laptop for USB debugging.
then try "adb devices" it will list device which is connected.
after then when you go for "fastboot" it will wait for device.
What is that? while we listing via "adb device" device is there but in fastboot it is not there?

The simple solutions is that, You have to boot your device in fastboot before invoking command of "fastboot"
for that you need to just go for "adb reboot bootloader" and follow screen instruction.I t will reboot your phone for fastboot.
Now invoke "fastboot" command, It will run as usual, If still face problem then grant command window administrator privileges and try again.