Windows 7 USB disks not recognized although USB mouse & keyboard are

[chaya]

Hi,

(I'm not sure if this issue should be posted under hardware or software)

Up until a few weeks ago everything was fine. As far as I know, no new hardware or software was installed on my Win 7 PC.

During the last few weeks, external disks or disk-on-key connected to the PC are not recognized. They do not appear in “My Computer”, there is no icon in the taskbar and of course no pop-up comes up.

I must say that the disks do get power for a few seconds and their indicators flash (on the disk itself) but after a few seconds it seems like the power is lost.

A keyboard and mouse connected through USB work fine and if I switch them to other ports and use the free ports for an external disk, the disks still don’t work. Of course I tried all ports and different external disks and disk-on-keys.

I tried booting in Safe Mode but then the mouse & keyboard didn't function.

Perhaps I should uninstall all the USB components that appear in the device manager and let them be recognized from scratch, but doing that my mouse & keyboard won’t work either and then I’m stuck. That way I won’t be able to even reset the PC.

Does anyone have an idea how to solve this? It’s really bugging me and searching online I couldn't find any similar problem (where mouse & keyboard work) and all solutions that I tried didn't help.

Thanks for your efforts!

 

[Josephur]

System Restore may be your quickest savior, but without more information it's hard to say what's going on. My guess is that somehow mass storage device over USB drivers are missing or corrupt.

Have you tried "sfc /scannow" at an administrator command prompt? Might restore what's missing..

What is going on in device manager when you plug in a mass storage device? Also what related logged events in the event viewer?

 

[chaya]

Thanks for the quick reply.

I tried System Restore but nothing changed.

When I plug in a mass storage device nothing changes in the device manager and no event appears in the event viewer.

sfc /scannow completed successfully and didn’t find any problems.

If mass storage device over USB drivers is missing, how do I bring it back?

Any more ideas?

 

[Josephur]

Hmmm perhaps try installing the correct USB chipset drivers for your motherboard.

 

[Trouble]

What we never seem to learn until sometime after the fact, is that often these settings are controlled by someone else.
Like in a work or domain environment such settings can be altered using Group Policy or simply by editing the Start Value of USBSTOR in the registry to 4 instead of 3.

http://support.microsoft.com/kb/555324
http://support.microsoft.com/kb/823732

 

[chaya]

Hmmm perhaps try installing the correct USB chipset drivers for your motherboard.

How do I do this? Where do I find the correct drivers?

 

[chaya]

What we never seem to learn until sometime after the fact, is that often these settings are controlled by someone else.
Like in a work or domain environment such settings can be altered using Group Policy or simply by editing the Start Value of USBSTOR in the registry to 4 instead of 3.

http://support.microsoft.com/kb/555324
http://support.microsoft.com/kb/823732

This is a personal home PC. No one touches it besides me and I definitely didn't touch the registry.

 

[Pauli]

Pure guesswork:
1. set BIOS to Safe Default, even if you haven't changed it, just do it - while you're there, check if BIOS shows your disks
2. try with only one disk at a time, shift ports, then shift disk
3. try your disks in another computer = friend's or so