I bought a used motherboard from ebay for cheap and I want to test it. But i do not have a extra pc case for it.. So what i did was i pulled out all the cables from my working pc and fixed it on to the new motherboard. (I dont want to take out my good pc motherboard from the tower) I left the motherboard outside the case and fixed all the cables from power, cpu and fan, floppy drive, 1 hard disk, 1 stick of ram and video card, and front panel connections I did not get a signal to the monitor!!!! is it not working because I left the motherboard out of the case .. ???
You should be able to run it outside of a case without any problems. However, you should just spend the time to set it up correctly and test it, in the long run you'll end up doing a better job and probably saving time.
outside of the case is alright at i do that when testing boards. check to see if the cmos jumper is in default position. also disconnect all drive cables as an ide cable in reverse can cause a non-post situation.