Just finished putting everything together and plugging everything in, but my PC wont even power up, no lights or beeps. Nothing. I really don't know whats wrong, this is the first time I put together a rig without any help.
It sounds like it's time to work through our troubleshooting checklist. It was created to troubleshoot this exact type of problem. Perform all the steps in the checklist and let us know how it goes. There's a link to the checklist in my signature.
could be the mb is shorted out. did you use the brass standoffs to keep the mb from shorting out on the mb tray and check the mb i\o shield for it hitting the usb or the bottom of the mb and causing a dead short.
check the power supply. pull the ps from the case and hook up a fan to it and then use a paper clip and jumper the green wire to the black ground. if the ps is not doa the fan on the ps should come on and output some voltage.