How to Resolve Media Card Reader Issues?

Hello there,
I am a mobile/cell phone repairer and I also have to perform tasks like data uploading in mobiles etc (usually). I have installed MS XP service pack three (3) on my office/lab PC and I am having an issue with my media card reader.
The problem I have with my media card reader is that it stops working after a while and than again use to starts working again properly automatically after a minute or so. Mean, my media card reader pauses its functionality (while working) suddenly and than after some time it restarts its motion again (after getting hanged for a while).
This issue is very much time costing and that’s why t is very irritating for me because it develops hurdles in my professional tasks. Whereas, I have tried different things to get out of this problem but none of them worked for me to avoid this issue.
For the solution I checked my PC for USB ports hardware issue but its report is satisfactory and my pc has got no such problem. I also have tried plugging it (card reader) into different ports but the issue is concerning with all. The method of re-installing the USB human interface drivers has also been applied by me but this neither worked.
In the end I would like to share that I have inspected my media card reader for hardware issues but its fine in terms of that and it works properly on other machines.
Well, honestly I have give up now to fix this issue myself and before going to a local computer’s expert shop I would love to get a clue here to fix it.
I really need to learn, how to get rid of media card reader issue in XP?
I am waiting for any suggestion with great curiosity and any clue will be highly thankful from my side.
Hoping and waiting.
