Assuming these are federal student loans, rehab is discussed in the link below. Student loans follow the borrower for life. If your loans are in default, the owner of the debt can garnish wages and tax refunds without a court order.
Rehab is the process of removing the default status. You agree to make a certain number of on-time payments and the CA agrees to remove the default status and send the loans back to the D. of Ed. If your wages are currently under garnishment, they will remain under garnishment until the rehab process is complete, and the garnished wages do not count towards your rehab payments.
If your student loans are in default, call the D. of Ed. and find out who currently holds the loans. Call that company up and discuss rehab.
http://www.ed.gov/offices/OSFAP/DCS/rehabilitation.html