multiple errors and problems galore

I got my Folger Tech RepRap 2020 Prusa i3 nearly 2 weeks ago. Right out of the box, the board looked like it had been stepped on. but I expected as much from USPS. several prongs were bent out of line, nothing a pair of pliers couldn't fix. I made darn certain that I built everything right the first time by quadruple checking the wiring and the instructions. Everything was smooth until I plugged it into my PC. To start, I had a mintemp error. none of the solutions online provided any help, and replacing the thermistor in the bed didnt help either. The second time I started up my computer, I had another error on arduino.

"avrdude: ser_open(): can't open device "\.\COM3": Access is denied."

I went back to the forums again, nothing helped. And somewhere in the process I dug myself deeper as now the entire printer itself is no longer recognized. ('unknown device' under 'other devices' in device manager.) the driver will not install when I unplug/reset the printer. The mintemp error is still displayed on my LCD.

Is there any way I can start from ground 0 and start fresh in terms of software/drivers. And any idea on why the heck I have that mintemp error in the first place. all the wiring and hardware is fine from my naked eye, and exactly as the photo diagrams. Im basically at the point where I am ripping my hair out and smashing my head on the table trying to figure anything out to solve these issues.

I haven't called Folger because I work odd shift hours. I dont know if their phones are 24/7 but Id imagine it would be odd calling them at midnight about this.

I would be glad to take as many pictures and screen shots needed for your help.

"Access is Denied" means that something else is keeping that COM port open. Have you tried restarting the computer, then trying again?

It could also be a driver problem. Look on the main board and advise on what ICs are on the board (model numbers). One of those will be a USB to Serial chip and can search for drivers for that chip.

I haven't called Folger because I work odd shift hours

Then email... I definitely wouldn't have waited 2 weeks to try and troubleshoot.

I have figured out the driver issue, and restarted the computer several times, the printer does not display as any other Com port other than com3. however the 'access denied' and 'mintemp' problem still persists.
this is the full message displayed when I attempt to connect and upload RAMPS

"
Sketch uses 91,002 bytes (35%) of program storage space. Maximum is 253,952 bytes.
Global variables use 3,672 bytes (44%) of dynamic memory, leaving 4,520 bytes for local variables. Maximum is 8,192 bytes.
avrdude: ser_open(): can't open device "\.\COM3": Access is denied.

avrdude: ser_drain(): read error: The handle is invalid.

Problem uploading to board. See http://www.arduino.cc/en/Guide/Troubleshooting#upload for suggestions."

OKAY
SO

I dont understand how this solved the issue, but I went into device manager, right clicked the arduino board under 'COM3' and selected properties. I then selected 'port settings' tab and 'advanced...'
another window pops up, in the bottom left is a drop down menu for selecting the port number.
I selected COM2 just at random, saved and accepted changes. on arduino it no longer displayed any COM Connections. unplug, then re-plug the USB cable from my PC. arduino then said the printer was on COM2, and uploaded RAMPS successfully.

all that is left now is to figure out the damn mintemp error