Wifi problem - constantly disconnecting

Hi,

I've got a problem with my wifi network. My connection just drops constantly, but it has become so much worse in the last few days that it dropped 3 times just while I was writing this post.

So the problem started last year when I was still using Windows 7, then I changed to Window 8.1 this year, and now I'm using the Windows 10 Evaluation version - I know this can cause incompatibility problems, but as I said, the problem was present even under Windows 7. It started out with the wifi disconnecting about every 30 minutes, sometimes more, sometimes less. At times, my wifi network goes into 'limited' connectivity, sometimes it just disappears for a few seconds. Sometimes I have to reconnect manually, sometimes it comes back by itself.

Other devices are using this wifi network sometimes too, 2 other laptops and 2 phones. None of them have any problems with the wifi like my laptop, but nevertheless I tried to rule out interference by disabling all of those devices, changing the wifi channel (to channels 1/6/11), but to no avail. There has been a time when I got no disconnects at all for about a week, using only this device, but that only happened once. (And no, no one is leeching the wifi network.)

On my own device, I updated every driver many times, turned off power saving, disabled shutting down the adapter, checked the power saver settings and many more. I've got no idea what causes this and I'm really frustrated by now, because nothing I try seems to work.

I'm using a Fujitsu Lifebook LH532 notebook with an Intel Centrino Wireless-n 2200 network adapter. Any help would be appreciated.