Since upgrading my wife's SGS1 to the Telecom official load of 2.3.3 she has had an intermittent problem of the screen going blank and displays nothing when the home button  is pressed , SMS or calls comes in.  Nothing brings it back to life apart from   force powering off or pulling the battery out. This was happening several times a week so I assumed it was an app that was causing it.  The fone is 18 months old.

After a couple of weeks of this  happening I factory defaulted the fone and left it a week and it seemed to have fixed it. I restored the backup, upgraded the default apps and put back Swiftkey, Whatap and Air NZ Mpass  the three apps she mostly uses and left the rest as she also has a tablet.  It seemed OK for a further couple of  weeks but it's started happening again. 

I've told her next time it happens take it back to the local Telecom store and show them as no one will believe it  if you take it back working again.

No doubt it will be sent away with some reason like "water damage " or the like being the answer from Telelogistics because it's out of warranty at which time she will have a go at the CGA.

Anyone  seen this before and if so any ideas ??

If we weren't treated like a tech 3rd world here and  didn't have to jump thru so many hoops I would buy a Nexus 4 and give her my old SGS2

TIA.