I have a baby lock ea-605 serger

Assuming that (a) you have tried installing new needles, (b) the new needles are the correct system for the serger and the right size (typically size 14 for medium-weight fabrics, size 11 for lighter-weight fabrics), (c) the needles are installed correctly (inserted all the way up into the needle bar and facing the proper direction), then your machine is likely out of time and / or has a defective part such as an upper / lower looper. That will require professional attention to correct.