It is almost impossible to do it by one's own hand. It involves critical microscopic wires and plastic perfectly measured case. Instead of creating one, I advice you to buy 1.
Yes, you can get a USB to RS232 converter (aka USB to Serial).
yes delete everything on your usb first
If the computer is connected by a USB cord to a powered USB switch, then many connections can be made.
cookies.
yes make sure the usb pen is set on fat32 format.
They do make universal USB serial adapters. They are very affordable.
no
The way one could get a make a simple true or false USB input for a program they are making would be to use USB protocol language. One program for this simple USB programming would be PsUSB.
Yes they do make car stereos with USB. Double check that the USB will read memory cards or flash drives and that the USB is not just for mp3 devices instead of storage devices.
Yes. USB devices should work on any computer which has USB, whether its a notebook or a desktop should make no difference.
There are various places where one can learn how to make a USB boot device. For example, Tech Republic, Tweek and Trick, Rufus, PoweISO and Make Use Of.
One good way is to get Ultimate Boot CD 4 Windows and use it to make a bootable USB. It will give you some good tools on that drive.