hi im just starting to learn this arduino and just bought a Nano V3 and Uno R3.
so
where i can download the driver for Nano V3 ATmega328P and and UNO R3 MEEGA328P??
and start basic code like blinking led and display text to LCD.. btw i also bought LCD module with IIC/I2C 1602.
thanks
Download the Arduino IDE from here and install. The IDE comes with drivers for real Arduino boards. Some clone boards can come with USB to TTL converters that are not supported. You will have to identify the converter and get drivers for it.
Ha Ha!
Presumably you have installed the Arduino IDE.
But the big question is - what have you bought? It depends on whether you bought genuine Arduino UNO and Nano, or a "clone" of one or both. Many UNO clones are not really UNOs at all. 
Many or most "clones" use a CH340 USB chip which does require a different driver - but is otherwise a perfectly good and working unit. If you were using Linux (Mint), you would not be asking as almost all drivers are built-in (but there is another configuration point to be addressed).