I was just wondering if hidden power affects ghosts since hidden power is a normal type and they don't affect ghosts but hidden power's type is different depending on the pokemon who uses it.
Yep, Hidden Power does hit Ghost types, except for in the case of Hidden Power Fighting.
Check the chart and explanation as to why it cant be normal.
http://bulbapedia.bulbagarden.net/wiki/Hidden_Power_calculation#Type
Type a Pokemon name, type, move, ability to see instant results.