Wifi shows full bars but runs slow or not at all

Hi everyone. Got some Wifi issues that's slowly driving me crazy.

I have a desktop pc with Win7 and a usb Wifi adapter connected. Now, my wifi is showing full bars and what appears to be a strong connection, yet the internet hangs and is unable to load an entire page, if it even works at all. A lot of the time it will jump from full connection to limited access, and it took forever to identify the network.

All other computers in the house have great wifi connection - however, they are all laptops. Mine is the only one dependant on an external wifi adapter.
I have tried several adapters and have had problems with all of them, never able to maintain a stable wifi connection. One had a decent connection but it was not entirely stable and usually hung in the low bars. It worked with my computer being in the same room as the router, but I've had to move it one room over.

I've tried resetting the router.
I've tried disabling both router firewall and windows firewall with no change.
I've tried installing and reinstalling the latest drivers for the adapter.
I've tried putting the adapter and the router right next to one another, no change.
The channel I'm using (2) was shown to be the one least used, I could try and switch channels but we really don't think we have that much traffic out here as I live in the countryside.

My adapter is this one: ALFA AWUSO36H

The most frustrating thing is that it looks like the wifi is working with full bars, yet it doesn't work at all.

Any help is greatly appreciated. Thanks for reading.

Possibly the USB port going/gone bad. Perhaps try another port, if the machine has one.

Please post the Make and Model Number of the Computer.

Thanks for the replies. I don't think it's a problem with the usb as I have a lot of usb ports on my compy, and I've already tried several of them. I'll try starting in safe mode and see if it makes a difference.


------------------
System Information
------------------
Time of this report: 4/27/2013, 10:57:22
Machine name: BRUTUS
Operating System: Windows 7 Home Premium 64-bit (6.1, Build 7601) Service Pack 1 (7601.win7sp1_gdr.130318-1533)
Language: Danish (Regional Setting: Danish)
System Manufacturer: Gigabyte Technology Co., Ltd.
System Model: GA-970A-DS3
BIOS: Award Modular BIOS v6.00PG
Processor: AMD FX(tm)-8150 Eight-Core Processor (8 CPUs), ~3.6GHz
Memory: 8192MB RAM
Available OS Memory: 8174MB RAM
Page File: 2674MB used, 13670MB available
Windows Dir: C:\Windows
DirectX Version: DirectX 11
DX Setup Parameters: Not found
User DPI Setting: Using System DPI
System DPI Setting: 96 DPI (100 percent)
DWM DPI Scaling: Disabled
DxDiag Version: 6.01.7601.17514 32bit Unicode

Well, I stand corrected.
Turns out I actually didn't try out all my usb ports yet, and that I have a couple of faster ones (dunno if usb2 or usb3) that solved the issue for me.

At first the issue was only solved for a while - the internet became a lot faster once I switched the usb, yet after a few moments it became unstable. I moved the computer to the same room as the router is and then couldn't get the internet to connect even though I saw it with full bars in my list of available networks. Turned out I had entered the wrong network code into the adapted utility I'm using. The program never informed me of this, but created a profile for the network based on the wrong key. Thankfully I went back and rechecked and got the right one, and now it finally works.

So, in conclusion, and to anyone who are facing similar issues in the future:

- Check what usb your adapter is connected to/compatible with. It might show full bars strong wifi and still be bogged down due to the usb.
- Make sure you're using the correct network key.

Thanks for the help and suggestions!