If it won't boot into Safe Mode either, then I'll guess that you bumped a connections while vacuuming. As such, I would re-seat all the connection inside and give it another try.
Of course, since a vacuum carries a LOT of static electricity when it's running, it's also possible you shocked the motherboard.. Not good if that's the case.. So EXACTLY which "splash screen" are you referring to? Does it make it to the black "Windows XP" screen with the scrolling blue dashes? Or does it not make it past the motherboard/brand name splash?
Hope this helps.