Failure in connecting to PC via USB

sounds like there is a fault with the charging of the phone & it is trying to draw too much power.
clean the connections both in the phone, pc & cable & try again.
try connecting to another pc, if you get the same message, fault is on phone.
if you connect ok, try re-installing  the phone software on pc.
It could also be a fault on your power side of the PC.
is the phone connected directly, or through a powered hub ?
Phones are very sensitive to power fluctuations and ideally should connect to a single pc usb socket, and not through a hub which can try and draw extra power to supply other accessories.