alabu55's solution was the answer to the same problem I was having with my Epson Stylus NX215. It was working fine and then suddenly it wouldn't print, wouldn't turn off, and after I disconnected it and reconnected it back to power, it wouldn't power up again. Checked all the usual suspects and then found this thread. The POWER SURGE SOLUTION worked perfectly! The weird thing is, the power bar did not indicate any surge problem so it hadn't even occurred to me to check that specifically. Anyway, I don't usually post to forums but I joined this forum today simply to THANK YOU and post my success with your solution in hopes it will assist somebody else if they search for an answer to 'Epson Stylus NS215 printer won't turn on'.
Thank you for your clear and concise instructions -- it worked immediately. You just saved me worrying about how I was going to afford a new printer.