The Lenovo M58 desktop PC (2009 and 2010 T4L Rollout) has a standard VGA port, but it also has a “DisplayPort” which can be used to connect a second monitor very easily – all you need is an appropriate DisplayPort adaptor cable. This video shows how to set it up.
All you need is a DisplayPort to VGA Adaptor such as one of these.
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Lenovo M58 desktop PC (2009 and 2010 T4L Rollout) has a standard VGA port, but it also has a “DisplayPort” which can be used to connect a second monitor very easily