Seagate 1TB external USB drive not recognized.

Last week i purchased the Seagate ITB external drive from Target. I connected to my laptop. It worked like a charm. I wanted a backup of my desktop. So i connected it. ( I had windows 7 in my laptop & XP in my desktop). The drivers were updated in my desktop but somehow the drive was not showing up in "My computer". I trid all the tricks i knew. I even started pulling my hairs out of frustration.
My USB slots were working fine. I was able to move files thought it to my pen drive & my nokia cell phone also. But somehow this 1TB drive was not working..

I removed the drive connection from the front USB slot & connected it to the rarely used back USB slot and it worked !!!!!!!!!!!!!!!! Dont know why & how but it is working properly now.

The only sane explanation i can come up is that the back USB ports supply more power than the front (theoretically both should supply same power but due to the internal configurations there is a slight difference in the power supplied via front USB port)