can't upload sketch to pro-trinket

I have this strange problem I can't solve...
I connect my Arduino pro trinket to and USB port with the mini-USB adapter. When I connect it the red led starts flashing, indicating bootload mode.

However the IDE can't connect for some reason. All it sees is COM1

if I connect the Arduino to the USB, a USBtiny device appears in my devices

but no COM3 4 or 5

I'm using windows 10 now, can't rememeber any similar problem when I was still at win7. I reinstalled the environment (even upto 1.6.13 now) and board drivers to no avail....

Am I missing something?

after a while I get

avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 10 of 10: not in sync: resp=0x99

RESP sometimes is 9f

You need to search for and read the getting started guide for the Pro Trinket on Adafruit's website. A Pro Trinket is not the same as Arduino Pro or Pro Mini, so you are selecting the wrong board.

yes, I installed the trinket drivers for windows, but I do not see the trinket in de list of devices

You have to add the Adafruit boards with the boards manager:

ok it seems to be working, but no clue why
I have added the aditional board definitions I found on the adadfruit site to the programfiles (x86) adafruit hardware directory. Then the IDE saw the trinket. However when I compiled the code the IDE stated there were two wire.h definitions. So I uninstalled the IDE once more but this time deleted the whole adafruit directory in in programfiles (x86).
Then re-installed only the IDE, not the boards et voila...everthing working fine...

only problem now is that with the same code the characters on the 64x128 display (inc adafruit logo) are twice the size they were beofre)

oqibidipo:
You have to add the Adafruit boards with the boards manager:
Arduino IDE Setup | Adding Third Party Boards to the Arduino v1.6.4+ IDE | Adafruit Learning System

Yes I had done that with no result