How do I get inside a 'PHILIPS' PHP X19 Model 900W PC Monitor?

I have the above monitor and it is exactly 3yrs old. It has now developed the common problem of going into standby when switched on. As has been widely reported it could be the power supply which is at fault. As an electronics engineer, I'd like to have a go at fixing this. Problem is gaining access. I have removed the stand and the two small screws at the lower rear panel. There are four narrow slots on the lower edge where a blade can be inserted to separate the rear casing, supposedly. This does not seem to work and I don't want to use excessive force and damage the unit. Has anyone else opened this monitor? Any help would be most appreciated.