the camera won’t start when the memory card is in it but the camera will start without the memory card..what should i do?

I have a canon powershot xs110is digital camera and when I hold it vertical the screen goes blank? Any Ideas? Thanks!

When I use flash with my canon powershot A640 the photos turn out dark. when i turn off the flash, the photos although not of optimal quality are better. why is this so? Has anyone the same experience? I will appreciate a reply or run through. it was not like this when i first bought the camera (mine is brand new) maybe i just turned a wrong knob??

I am thinking about buying a Canon PowerShot S5 IS but have a few concerns. Mainly, I am worried about buying the camera and then having the next generation PowerShots be released very soon after.
Should I go ahead with my purchase or hold out for the next generation Canon’s to hit the market? Any idea when that might be?