USB Problem

try reinstalling USB drivers, or Remove USB controllers and let the OS auto detect and install

is it with any usb device on either port?
yes first try re-installing the usb drivers

NOTE: you may have to enter into SAFE MODE (by pressing F8 on startup)and remove all usb drivers there to completely rid system of drivers

demonhale - Thanks for replying, i tried that but still no solution

wwwben - yes its on any USB device, i tried the back and front USB sockets but all are doing the same, i realise that it cant be the hardware itself as otherwise i would not get anything at all from them, its quite strange actually, i remember the USB disabling itself before on a previous computer, but it was easily corrected by re-enabling USB in BIOS, but this time i dont know what or why this has happend, i may try what you suggested using safe mode.

I entered in safe mode and tried that but still no luck

If youve done all software checks, better open up your box and check the jumpers and connectors on the board that enables both front and back USB ports, check for loose jumpers which is the common culprit...

Thanks demonhale il try that today.

Another problem with USB is the power. If you have too many devices plugged into the ports it can reduce the voltage available, the same can happen if a device develops a fault and draws more current.

It's a process of elimination by trying different device combinations. Or using a powered hub for some devices.

Someone else said the same as yourself about using a powered hub, i have 4 USB devices plugged in but thier not all being used at the same time, in fact it was only the modem on constant, and the PSU is 550 watts.
I do get a message when i plug any of the USB devices back in saying that the device has malfunctioned.

Sounds like the USB voltage or the voltage regulator on the MB may be the problem. There is a limit of 500mA available to power all devices regardless of the PSU capabilities.
Couple of things;

remove and reseat all the USB connectors, There is the issue of VOCs (Volatile Organic Compounds), basically atmospheric borne corrosives that tarnish connectors and create a high resistance connection. Removing and reseating will break the tarnish and leave a clean connection.

Make sure the MB is free from dust. Any dust around the regulator IC will reduce it's capacity to lose heat and reduce the current carrying capacity. So a spike as a device is plugged may be shutting the regulator down momentarily.

Cleaning a PC is something that is overlooked by many, removing the dust build up around fans, inside the PSU, around the MB and drives every 6 months or so will help to keep the machine running better. Especially important if you smoke near or while using the machine. Nicotine smoke is very sticky and will hold the dust in place.

Thanks very much chrishirst, i suppose a lot of us underestimate the problems that a build up of dust and other particles may cause, this is definately something i am going to do along with the other suggestions that ive had, i dont think ive ever properly cleaned inside any of my pc's before, apart from disturbing the dust while istalling new hardware. il give it a try and will keep you posted of the outcome.

chrishirst - It may sound daft, but what would you recommend using to safely clear most of the dust from inside my case, obviously i wont do something silly like trying to blow over the motherboard etc and risking droplets of any kind, but just wondering generally how you would go about it?
Cotton buds maybe? or would that be a bad idea?

um yeah looks like you may have a hardware problem on your hands.. maybee buy a pci usb card.

What christhirst said is actually a long version of what I said you should check...

Anyways you can buy a compressed air canister and use this to blow off some dust...

For contact points on your MOBO use an a pencil eraser for the grimed contacts...

Lastly you could use a regular Paint Brush to dust off some remaining dusts...

Thanks demonhale, i will give everything a good check and a thorough clean while its open, i will probably try and get hold of a compressed air canister tomorrow.

It is possible that a software change messed up the USB stuff, go to Start > Run > Services.msc and make sure "Universal Plug and Play Device Host" is set to Automatic and that it is running. Since every PC is different, take a look around and see if there is anything else that may be causing it. Some services get disabled for software changes, patches, and just about any change, and they often don't get reset.

Good Luck!