i keep getting this message : "avrdude: ser_open(): can't open device "\.\COM3": Access is denied" everytime i try to upload something to my arduinos pro mini using cp2102 ,
i already installed the driver .
i own a similar to this one : New Pro Mini atmega328 5V 16M Replace ATmega128 Arduino Compatible Nano | eBay
Access denied is most likely an OS thing.
However "\.\COM3" doesn't seem to be a syntaxis Windows would throw at you.
You should mention what OS you're on.
If it isn't Windows, i can't really help you.
If it is Windows, see if your CP2102 really is at COM3, and also if there aren't other devices reported at COM3.
Like a frickin' dinosaur Micorsoft serial mouse.
If you have such ghost devices, disable them in device manager and reboot.
Reboot is mandatory because the COM port will still be reserved for the (now disabled) device.
Of course a lot of guessing going on here.