No Video signal- PLEASE HELP!

[adr3naline fix 0]

I bought a 4 channel setup off of ebay.

(4 WIRELESS Camera +4CH DVR Security Surveillance System) is the name of the auction since i cant post a link within the first 5 days of membership on this forum

 

I plugged a camera in 20ft away, and then activated the camera in the program...it just brings up a error that says "NO VIDEO SIGNAL". Stays either a black or blue screen

 

 

I need help baaaaaaadddddd

 

PLLLLLLLLLLLLEASE HELP ME!!!!!