If something was mistaken with your mobo it would sound a few times when it started up. Try added guardian , wiggle both cables, and im guessing if a new harddrive did you place a windows or linux or whatever gracious of artefact cd in the cd/dvd rom?
I think it should be like this. Spray the cleaner on a rag or paper towel. This is the important to care about it. DO NOT spray it directly on the computer to avoid creating too much moisture.