Here you can download USB and ADB driver for your A7000 smartphone by Lenovo comes with MT6752M cpu from mediatek. This driver will also work for 3G, 4G handset. Just download from below link and run it. Remember this driver for only PC Windows.
Download Lenovo A7000 USB/ADB Drivers Official
Supported OS : Windows XP / Windows Vista / Windows 7 / Windows 8 / Windows 8.1 / Windows 10 bother 32 and 64 bit