On unpluging the monitor (Iiyama Prolite e435s)all settings are gone and menu buttons behave eraticaly. On holding down the + and - buttons and powering on I gain access to a hidden menu. From there I can restore the right settings which only last untill I unplug the monitor
Computers & Internet - iiyama - ProLite E434S 17" LCD Monitor
Answers & Comments
When you have strange symptom like this, the first place to look will be the power supply section, look for bad caps (leaking/bulging tops) first.
http://s807.photobucket.com/home/budm/allalbums
http://en.wikipedia.org/wiki/Capacitor_plague
http://www.badcaps.net