you just need two 555 based circuits, and three relays.
nothing fancy.
555 circuits for dummies:
http://www.uoguelph.ca/~antoon/gadgets/555/555.html
middle of the page has an oscillator circuit (google for more), which provides a tach signal to the mobo. also has how to make a switching operation with a delay, to a relay.
http://home.cogeco.ca/~rpaisley4/LM555.html
more circuits.