MBP won't recognize secondary monitor... Help!

i have mid 2010 mbp running lion. when @ home use secondary monitor primary (lower , upper bar on second monitor , mbp monitor desktop picture) using dynex hdmi connector. of sudden won't work. plug adaptor in , mbp screen flashes blue goes how ( secondary monitor doesn't recognize it).

called applecare , had me few things. had me reset of shift control option believe, restart command p r believe , restart in safe mode ( holding shift) had me run verify disk , came clear. worked 1 yesterday today won't. hooked moms dell monitor know it's not monitor.


connector? software problem mbp? ideas great

 

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