Sync Error, 5+ Hours of Frustration and No Hope

I've spent so much time trying to upload some code to my Mini Pro and all I get are three flashing lights on the Rx before the "avrdude: stk500_getsync(): not in sync: resp-0x00"

I bought three mini Pros and have the usb2 serial adapter. The first PCB I soldered had the transistors backwards thanks to some mis-labeling. The second PCB I soldered went in beautifully, and now I'm trying to upload the code to it. The Arduino USB2serial either says that the COM port is already taken, in which case I have to unplug and plug in the usb and then reboot. Other with I get that sync error.

I've tried pressing the button on the mini pro when the three flashes happens, no luck.

I've tried burning the bootloader: This report would have more information with
"Show verbose output during compilation"
enabled in File > Preferences.
Arduino: 1.0.6 (Windows 7), Board: "Arduino Pro or Pro Mini (5V, 16 MHz) w/ ATmega328"
avrdude: usbdev_open(): did not find any USB device "usb"

I've spent hours looking for a solution and I'm just about to give up on this project.

I'm using a really good soldering iron (Hakko). Could it be that the mini pro is burned out? There was no issue and there's nothing that looks burned (the mini pro power light comes on). Mayeb there's a special temperature?

I'm out of ideas. I need help!

Hi.

I used this kind of arduino for some projects, and as you a USB to serial adapter. And Even programming them often, some time I got this issue.
What I learn: my win98 box ( 8 years toshiba sattelite pro ) work better than my win7, 3 years asus laptop.
I use the usb to serial adapter connection gnd/5v/rx/tx to the arduino with an old audio/cdrom cable connector.
To program the arduino, I click on upload, and wait to see "Binary sketch size: XXXX bytes (of a 30.720 byte maximum)" on screen and press for 1, 1 1/2 sec the reset button on the arduino, if I got sync I can see on my usb adapter a green led ( data transmission on progress ) starting blinking. If not, I start it again, some time I need 5-6 shoot to get it, most of the time it's at 1st attempt.
Board option I chose arduino mini pro 5v16mhz Atmega328
Serial port com1 ( cp210x usb to uart )

On my 1st attempts I was so frustrated as you.

Remember TX of adapter to RX of arduino, and RX of the adapter to TX of arduino