yeah... you'd think this wasn't too much to ask but it does cause problems and what you need to do is paste it over to PowerPoint in two chunks (zoom in, line them up, group & then scale if required)
Basically, the table truncates at a certain number of columns because it's too large to fit on the clipboard.
I know it sounds a bit lame - exactly why a few columns of Excel don't fit on your Windows clipboard when your swapdisk is set at 100's of mB has never been fully explained by my Tech guys who curse Microsoft and then ramble on about hardware, memory & graphics cards in the hope that I'll lose interest and not realise they don't actually know themselves.