If you fail to make payments for your student loans, these loans will eventually go into default. Defaulting on a student loan is pretty much the same as defaulting on any other type of student loan. By going into default, your credit score begins to take a hit as the missed payments will show up on your credit report. Eventually your lender can file a lawsuit to recover the money lent for the loans. These lawsuits can eventually lead to wage garnishments and here in California a creditor can garnish as much as 25% of your wages.
Can student loans be discharged in a bankruptcy? It is possible to eliminate student loans in a bankruptcy but not very likely. Based on current bankruptcy laws, to discharge your student loans you must make a special motion to the court and show that the loans impose an "undue hardship" on you. Basically, this is very difficult to prove as you must show the court that you are unable to work and that there is no realistic chance for you to pay-off some of these loans.
If you are having problems with your student loans it is best to contact your lender and request a forbearance, deferment or income-based repayment plan.