Error when trying to upload: can't set com-state for "\\.\COM2"

Hi.
I am using arduino uno R3. it's installed correctly. but when i try to upload my program i face with this error:

avrdude: ser_open(): can't set com-state for "\.\COM2"
An error occurred while uploading the sketch

i reintalled my compiler and drivers many times. i reboot my system too. i changed the port number. but none of them worked.
Does anybody know how should i fix this error?

The FULL error message would be great at this point as your issue is much too generic to even hazard a guess.

What and how to post is mentioned HERE