NOT modem related, but Computer, Hardware.
What whiring are you talking about?
Q - Where the whires from the power supply should connect?
A - Any connector they fit. They are one way, make sure they are connected with the correct orientation.
Q - The fans whires?
A - Normaly, to any 3 pins connector available. It's possible that there is some printed label near them.
Q - The whires that connect to external devices?
A - Same shape and size. If colour coded, SAME colour.
Q - the whires for the front pannel?
A - Check your manual. If you don't have the printed version, you can get the electronic version as a PDF file from the manufacturer.
(found that link in about 30 seconds using a search engine and doing some navigation on the eMachines web site)
http://global-download.gateway.com/GDFiles/Document/User%20Manual/User%20Manual_eMachines_1.0_A_A.zip?acerid=633933437244339685&Step1=DESKTOP&Step2=W%20SERIES&Step3=W3107&OS=ALL&LC=en&BC=EMACHINES&SC=PA_6E
Q - The motherboard itself?
A - Are you kidding? It's a printed circuit board!
Electro, June 2012