USB third device not recognised -Toshiba L750 WIN 7 64

USB conflicts on Toshiba L750/L755

All win updates are current - Running win 64 7

Done all windows steps to remedy USB issue including power management mods in device manager - Fault is evident when plugging in ext mouse, ext keyboard then external USB microphone preamp

If preamp plugged in it is fine, then mouse fine but keyboard not recognised

If keyboad first then mouse then preamp not recognised

Done everything except change registry

ALL ext devices work fine on a WIN HP tower pc and are fine on a Toshiba Vista 32 pc

Any ideas what to do now? Tried new keyboard Thanks

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You are probably drawing to much power from the USB line. Buy an inexpensive external powered USB unit an your problem should go away. Link provided for one example. Good luck.

This is one example but make sure you obtain a hub with external power.

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Thank you so much for replying. Regret to say I tried a powered hub and no change. As soon as a third external device is plugged in, it is not recognised, no matter what device, if it is the third it does not work

So now it seems I need to change bios or reload OS or alter registry none of which I want to do - so need to use another PC ! As mentioned, the devices work on a tower PC but not this make of laptop.

Here is the MSFT fix but I hesitate to touch registry as I do not know what this change does


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