Lenovo vibe K5 is not turning on anymore I have rooted  Lenovo Vibe K5 and i had installed CM 13 (Marshmallow) it was working good cause of some need, i had to install CM 12.1 (Lollipop) and i tried installing through TWRP recovery CM 12.1, I wiped Dalvik , Cache and System and installed CM 12.1 successfully and ask to reboot system and i clicked on reboot and after that it didn't turned on , not even in recovery mode by pressing and holding Volume + and Power button. Then i tried to flash it again  with pc but its not showing in CMD as well, it shows the error Device not found in CMD and in windows notification it shows USB Device not recognized. 
Big Mess . HELP
In this state, flashing the stock firmware still the solution. You need drivers for the PC to detect the phone.


Click here to get the USB drivers and the flash tool.
Click here to get the flash file (firmware).


Alternative download links:


Firmware 
Flash tool
Drivers


FLASHING STEPS:


First download firmware, flash tool and/or drivers from above links.
Extract zipped files to desktop or anywhere you'd like (You'll need winrar or 7zip software to Extract).
Open Driver folder and choose  Qualcomm_USB_Driver_Setup.exe file and wait until finish installation.
Open QPST.WIN.2.7_Installer-00430.1 folder and chose setup.exe file, open and install it.
Now open QFIL from the "C:\Program Files\Qualcomm\QPST\bin" path, Select Programmer option and click on Browse button and Select prog_emmc_firehose_8929.mbn from SW Folder file.
Click on Load XML button and choose
rawprogram0.xml file and then choose  patch0.xml file from the SW Folder folder.
Press and hold Volume Up + Volume Down and insert USB cable and wait until driver install are installed. 
Click on Download button and wait until flashing process finishes.


Oh, and you may need a video tutorial to make it easier, find it here: 
Flashing process