Some months aao I had a PROBLEM that seemed to right itself or at the time I thought it was solved when I replaced a power cord
I have Windows XP2 I have new Viewsonic monitor that has an Ipod dock(not used) plus usb ports and a card reader for my digital photos
They all ahve been working fine for some months . Yesterday it decided the card drives on the monitor were no longer there, and its not recognising USB devices apart from the printer and scanner, these include flash drivem exernal drive, seprate card reader
it is not recognising them on either the monitor ports or other USB ports in my tower, tonight I tried booting up without my printer and scanner connected which use USB and had no problem with and seeing if it made a difference it didn't even the USB that normally hase my printers or scanner in still did not regonise. Went into device Manager it has a USB devices unrecgonised but nothing was plugged in to them , does this indicate a problem with the USB Hub
I use a local comiuter guy and he said before it was a power supply can't see how when he has put in maximum power, had nothing else plugged in apart from computer tower and screen, went and saw three guys at retail stores computer tech setcion and they didn't have a clue what it could be this it is driving me crazy and iks making tings difficult since I need the stuff on mt drives. All the devices work on other computers so its not them. Can anyone help pleaseLocate every instance of both USB roots and hubs in Device Manager...
Right click each of them and select remove. You will get a warning message - ignore it.
Upon re-boot Windows will re-install them.
See if this helps.I did the ones that said unreocgnised devices and started doing the others but my mouse uses a USB so had to shut down manually , yes it remade the ones I had shut down but did not solve the problem and still have two saying unrecognised but the things I currently have plugged in ie printer and mouse are working but now my scanner isn't Sorry if i wasn't clear...
The procedure is to unplug all unneccessary devices first.
Then remove ALL instances of both USB ports and hubs whether you have a USB mouse or not.
Then re-boot.

Any un-recognised devices mean the drivers are not properly installed for that device.
The best method for this is to try one device at a time...if it doesn't work re-install the drivers ...I will try again I did only have my mouse and my monitor(for my card readers and extra usb ports) I am not very up on all this stuff. Is there as easy way I can tell which USB port relates to the the mouse so I can do it last or is it just by trial and error
plus the plug and play stuff I am having trouble with don't have any soft ware so no drivers to install I think the drivers are in XP? I've had the tower into the comuter shop and it works fine there but being intermittent I guess that's Murhpys lawFollow the steps outlined and we'll go from there...
Plug and Play should have been named Plug and Pray...
But lets solve one issue at a time.
Okay have uninstallaed and rebooted and still the same, showing 2 unrecognised USB devices,,mouse and working printer fine, the unrecognised ones seem to be the Monitor base which has Usb hubs built in and card readers, which normally show up as extra drives, they are not., and my Canon scanner, 5200F I have dowloaded and instlalled new updated drivers just in case, made no difference. Didn't fire up like it usually does when I boot up. Says unble to open Twain source, check connections and START toolbox again-did that
Sorry about the terminolgy to me anything that plugs in a USB port is device IRRESPECTIVE of whether it needs software. Does being a Snr cit count as an excuse

The plugs in not working are a failry new flash drive not registering, again used it to get photos printed off Wednesday and a portable Seadisk drive again okay a few days ago, the light is coming on so its drawing power but not showing as an external drive. These problems are the same ones I have been having intermittently for about 12 months now, sometimes they fix themselves, when I have taken the tower and the plug ins to the shop they work okay EVERYTIME, I have tested the plug in at neigbours house and they are fine. Borrowed a new powered hub from the shop 4port USB 2.0 hub, to see if that made a difference, it didn't, it wouldn't recognse that either
Thank you for your patience
IreneI don't know whether this is a Windows problem or a hardware problem, but I think it may be a hardware problem, a problem with your motherboard. If that's the case, then an add-on USB controller card could be the solution. This is a card that installs in a PCI slot in your computer. It adds 4 more USB ports on back of your computer.

This would be an easy installation for anyone who has installed RAM, sound card, or video card. If you've never done any such upgrades yourself and don't feel comfortable ATTEMPTING to install such a device, you could take it to a shop and have them do it.

Here's one card that I'll suggest if you want to go this route:
http://www.newegg.com/Product/Product.aspx?Item=N82E16815124008Soybean has given excellent advice...if a powered hub did not work chances are it is the MBoard here.Thank you yes I will be taking it into the shop whilst I am away for a few days I had suggested the motheroard as somoene else I had spoken to said it was a possibility, but the guy I used had said no it wasn't however I will take your suggestion along with me. I have asked him to do some diagnostics on it