this is a pc settings issue rather than an aimon one. The same would happen if you inserted some drawing tablets or ancilary devices.
The cause is the computer has an option enabled "boot from external media" or words to that effect, this means that the computer can boot (start up) from a memory stick or other form of memory if required....... but as some ancillary devices are incorrectly detected by this motherboard feature the computer will sit there looking at the usb port waiting to boot from it.
to resolve the situation you will need to switch this feature off in the BIOS, i DO NOT reccomend touching anything if you have no experience working with this level of computers and would suggest asking a reliable technician for a favour.
If you are "tech savvy" then you should find the option within the BIOS under the boot options quite easily..... if your motherboard allows you to turn it off!
hope this helps