Wiring a power switch to motherboard/pc not turining on

I have recently built my own computer and got it to turn on. however when i added a floppy disk drive, I must have accidentally pulled the power switch cable out from the motherboard and now i cant get my computer to switch on as i cant remember where the jumper cable went. Can anyone help me please, the case is a casecom 7770 and the motherboard is a MS-6577 Ver: 2.1. Thanks.