Yeah I was working on my Q605 this week, it is tricky getting that connector off. The black retainer arms are at least rounded off on the bottom side, so they will flex out by themselves just by pulling the PSU connector off. Having the PSU connector on that little leg on the bottom of the board makes it feel like pulling on the connector is flexing the board too...ugh.

The Q605/LC475 is a neat design for how small it is, but there's some real weak points in the design (see also: getting the floppy drive out without sending spindler-plastic fragments across the room)