set the right 'poort' arduino Uno

Hello! I use for several months of the Arduino UNO and Arduino Nano.
I warn you that my first experiences with these products.
from a couple of days, a strange thing happens to me, and not with one, but with all (5 pieces) using the USB connection say normal, not that mini USB, and I tried with another PC, but the result is always the same.
That is, I no longer set the right 'poort', because I always appear in gray and not black, so you can not set it and therefore it is impossible to load a program.
I consulted the website of Arduino, and I followed all advice, but the problem persists.
Can you advise me how should I do?
To clarify that I uninstalled Arduino 1.6.4 and other old versions installed, but nothing, and with the Arduino Nano version, (with Mini USB) NOT the problem occurs.
My PC has Windows 8.1, and the other thing my wife W7.
I hope for your help, and thank you in advance.

Mauro

If port is greyed out, but the Uno/Nano is plugged in, that means driver issues.

With non-working board plugged into usb, check device manager for unhappy devices, and reinstall drivers for them.

What serial adapter do the boards use? (Official ones use atmega16u2, but clones may use FT232 or CH340G; this is the chip located near the USB connector - if it uses 16u2, it's normal Arduino drivers, if one of the others, that's the part you need to install drivers for)

Hi.

I see you have posted your question in 3 different forums, this English one, the Dutch and the Italian forum.
It seems like you used google translate to get the translations to English and Dutch (my 1st. language), because the same errors are in both texts.
My Italian language skills are too poor to tell anything about that text.

I can also see that you have a personal webpage with your provider from Belgium, so it is possible you speak Italian (as a 1st language, because of your chosen name), Dutch and perhaps English.

But this way you are going to get answers in all three languages, and possibly the respondents have no idea what's going on in the other threads.
That is not helpful, and not very thankful to people trying to help you.
It is called cross posting, and is supposed to be not done.

As for now, you have had at least 2 replies that express suspicions that the problem might be river related, and both mention a possible CH340G driver that's missing.
Didn't you say you have this problem the last days, and have been using the Arduinos over last few months (which means they have worked for some time) ?
That would make a missing driver less likely, but it is still possible that you have some driver issue.

EUREKA !! I found the cause ...
Thank you for your advice, you are always welcome.
After several unsuccessful attempts, I even tried to install Arduino on an old PC that my daughter left me in
basement after her divorce + - 5 years ago, thinking it might work under another OS, but still nothing.
When I said that the problem was in the version of the Arduino in my possession, and that was it, I canceled my version (zip) and I installed the Windows Installer, and everything worked as it should.
Always so, the solution to a problem is always the easiest, but we never see ...
Anyway, thanks for your advice.

Mauro

Bellin:
EUREKA !! I found the cause ...
Thank you for your advice, you are always welcome.
After several unsuccessful attempts, I even tried to install Arduino on an old PC that my daughter left me in
basement after her divorce + - 5 years ago, thinking it might work under another OS, but still nothing.
When I said that the problem was in the version of the Arduino in my possession, and that was it, I canceled my version (zip) and I installed the Windows Installer, and everything worked as it should.
Always so, the solution to a problem is always the easiest, but we never see ...
Anyway, thanks for your advice.

Mauro

Aaaha!

That makes sense - if you use the zip version, it doesn't do any installation of drivers, though it's unclear why you needed this, since you say it was working.

Anyway, glad it's working now.