If you or someone you know purchased a Lenovo ThinkCentre M90z or M70z all-in-one computer — it doesn't matter when — you might want to see if you can send it back to Lenovo to avoid a potential fire hazard. Last month, the computer manufacturer voluntarily recalled 160,000 of the computers sold between May 2010 and January 2012 after two customers complained that their internal power supplies caught fire during use, and now the company's expanded the recall to 28,000 additional computers sold up through March 2012. In other words, every computer shipped since the systems were first introduced is potentially part of the recall, and it would behoove you to check. All you need to do is find the computer's serial number, and enter it at our source link.