can't upload to arduino uno

i got a arduino uno this earler this day, it worked for around a hour and now im having problems uploading. I looked up the problem and tryed to change port from1 to 38 but nothing happend, hope you can help me :slight_smile:

avrdude: ser_open(): can't open device "\.\COM38": The system cannot find the file specified.

Is anything connected to the Arduino? If yes, remove it, ALL of it.

If you open Windows Device Manager, an items with a ! in there?