yes, your using a pico psu... seriously, you paid $5 in a effort to save $10, and it is going to end up costing you $50...
1. any pico psu will not provide any regulated power on the 12v rail. this means that you need to provide regulated power--if not, you will destroy your motherboard, and other 12v devices..
2. car voltage can swing from 5v to 15v.
3. that adapter is only to plug something into the cig lighter, and does not provide any filtering.
4. the whine is a ground loop-- this is typical of using cig lighter plugs. i recommend hardwiring the pc to the battery.