USB burnout?

Hi all again, just a little USB problem or maybe its just me....lol

Is it possible to "fry" a usb port/header, without actually using its full Ma power rating ...all of the time, and also rarely used on full 480MbPS?

For some strange reason, my last two pc builds, my "whitebox's" have seemed to ...well, cooked their USB's, or i have....i cant understand why , or if it is even possible......

The last machine...had the standard 4 ports on the back, im not sure how they were actually "wired" though.....
Just looking at them.. i sort of assumed the bottom two were either connected each by their own erm header if thats the correct term, and the two sat atop them were maybe just "filching" off the same headers? therefore maybe each usb port could only handle half of the Ma power rating..lets call it 800Ma just for a number .... but anyhow.....

in the end none of them flippin worked as USB2.0 , and i bought a pci card with 5 usb...., and that card, handled everything i threw at it, in fact its still in the machine because i gave that machine to my freind.

And now lol my currant machine, is even stranger, i have a powered external hub.... that can supply i think 2000Ma in power and obviosly 480Mb in speed of transfer, and it has stilll happened , but not to every port
In fact im using a front USB on an extra header, that one seems ok.
I forgot to point out that i have tried various simple software based solutions, such as removing the drivers and using the standard ones on win 7, well ive tried it on three op systems, and done clean reinstalls, but for some reason its just "fail" lol......

Although maybe this is the excuse i needed to make a new machine! allways looking for an excuse to do that, but really i wouldnt want to because im poor lol and this whitebox is perfect for me... although i did see a Phenom quad 9xxx , mobo *some ecs one* and 2gb 800fsb ram for around 149£ ....

But does anyone have any ideas on the USB thing? i want a t shirt lol in fact il make it myself with a big red circle with a line through it reading NO USB!

Thanks again

Karl

 

USB devices are supposed to be manufactured to a specified maximum current rating @5v as are USB ports. Therefore unless the device is using more power than specified there should not be a problem. This power issue may occur if a device has accidentally be inserted the wrong way round for any reason (hardly possible but it still can happen). Therefore I would investigate the draw of whatever devices you use that have been used on both systems.