Hello,

A while back I removed a 3.5 IDE HD from an old PC running Windows XP I had been using. Putting this in a mains powered ´box´ and connecting to my Asus F55A laptop, running Windows 7, via a USB port has resulted in the pad mouse pointer going haywire. It moves around the screen without prompting. Disconnecting the external HD corrects the mouse pointer. I have checked the drivers for the pointing device and have erased the HD drive using C Cleaner after firstly extracting the required files. The problem still exists. Is it because of the two different OS´s, maybe? And is there anyone with any ideas on how to rectify the issue? It takes 5 minutes to position the mouse on an icon to click, and then it may jump off just as the pad is being pressed. Thanks.

In addition to my post. I have tried connecting a 2.5 EXTERNAL HD in the same manner as the 3.5 HD and all works perfectly. Thank you.

Try another cable and try another USB port and post back the results.

The most likely reason is the dodgy power supply or your external box creating electrical interference that propagates across all USB circuits. Mouse pad is connected via USB internally.

it could be a power grab from the USB drive pulling down the power of the USB controller. An external powered USB hub would help with that.

Or it could be the USB driver processing adjustments, but most likely the USB power is the culprit.

Sorry, made a typo, "power supply of the external box".

Thank you everyone. There is such a wealth of information out there. I can understand fully the external power thing, but is there anyway to rectify this problem?

Solution guys!!!!! Jiggled all the cables around and found that if the 7 pin? power connection entering the HD was held in a certain position the problem disappeared. Many thanks once again.