On a friend's computer there has been a regular problem mounting many different popular devices at any of the USB ports. If you plug in the devices, they are recognised, the computer connects and than disconnects. It continues this connect/disconnect sequence until you unplug the device. There is no problem with the hardware USB ports.... I am certain of this.
Some devices never have this problem. Others always have this problem. I have never seen anything like it before.
The computer has exhibited this behavior through several complete installs of OS software and devices. Anti-virus and Malwarebytes do not detect any type of problem. The antivirus utilized on this computer is Avast Internet Security Personal Anti-virus. It is using the latest updates. Malwarebytes is using the latest definition updates. The Firewall is Comodo (and has the latest updates installed.)
I myself have several computers and find from P2 up through P4, XP through Win7, I have been able to connect to all of the same devices and many more without any of these problems.
Somehow it seems as if one cannot blame Microsoft updates as my own computers are probably updated with the same software, but who knows, perhaps the Powerspec computer drivers have some incompatibility which I know nothing about.
By the way, the most recent device that the computer has treated in this manner is an Ipod Nano 8gb. Don't let it's relationship to Apple throw you.... It is only one of many different devices which this computer has reacted to in a similar fashion.
I have not seen any knowledgeable feedback regarding this problem anywhere and would appreciate some ideas and feedback.