Seems serious. Happened today : The usb wifi adapter (netgear a6100) ceased to connect to the wifi network, no matter how many times the router and/or computer were restarted, mac filters disabled, key re-entered, "repair" procedures re-launched, etc. I finally uninstalled the usb wifi adapter and its drivers - I now simply cannot reinstall it. It's not being recognised when I plug it back in any usb port, and the reinstalled driver seems to be damaged (crossed in the device management) yet any attempt to reinstall it from the internet or from the cd tells me that I currently have the latest working version... Pure contradiction. And no amount of restart or ccleaner purge between installation attempts change anything.

So, went to the shop, and changed it, assuming a physical problem on that usb wifi adapter itself. But the new one just shows the very same problem.

I don't truly expect the solution here, but, heck, after all, why not making a thread instead of a bitch-about-life post. Maybe someone will think of something I haven't tried yet...

My solution to every problem: disc format ;)))

Seriously now, I hope someone will be able to help you *fingers crossed*

Try and scan for viruses. A few days ago had a friend with the exact same problem. Turned out to be a nasty case of a computer virus. If it's true, you might wanna apply what bel_e_muir recommended. Best cure for a virus problem.

Recommended antiviruses:

1. Commercial soft - Kaspersky, Nod 32
2. Free soft - AVG, Avira, Avast

Pick a paid AV or a free AV - well depends on your budget.

Other programs:

1. Malwarebytes
2. The Cleaner

Pretty good in finding stuff that escapes to the AV. Again, make a choice.

I did scan with the Microsoft Security Essential, and with Spybot. Should I really try other softs ?

Maybe he/she has a cable connection?

Or mobile data connection and the endurance of a deity? (Forums via mobile are amongst the best tests of endurance and patience with tech that I can think of.)

Oh yeah. :D I tend to forget not everyone lives in the middle of nowhere like I do. :P

Yup, I'm using the cable right now (although I also have a tiny fully functional wifi laptop, that I've been using most of the day).

I totally agree!

Yup. The Microsoft stuff it's not stellar. I prefer some more reputable stuff, and not what Microsoft incorporates in Windows. For example, my AV is AVG (it's a bit of a resource hog in our days, but it's free and does a decent job for a free program). used to have Kaspersky, but it got a bit expensive to pay for a license every year ( still , arguably, Kaspersky remains the best AV). Also have Malwarebytes, which is quite good and does not eat a ton of resources. And as for a firewall i use the old Zone Alarm. Happy with the setup and it saved my arse for quite a few times.

check the windows logs

I'm using F-Secure Internet Security myself, I don't fully trust MS security. But, that's just me. Everything from MS seems so... commercial, you know? But it's only my opinion.

I had decided to use MSE after having asked on these boards, long ago. The consensus seemed to be that it was a good antivirus, despite my prejudice against microsoft.

I didn't say my opinion was a rational one. It is entirely unrational, subjective and prejudiced and I admit that. I can't say whether MSE is a good AV software or not since I haven't used it. I'm using F-secure and I'm really happy with it (I've never had any virus problems since installing it) but others may be just as good :)