Problems turning on EOS Rebel

My EOS Rebel does not turn on.
I check the battery (works fine in another camera)
It's fully charged.

Does anyone have any ideas of what I can check next or what the problem may be?
Thanks you
Tom McGuinness

Just a thought, have you closed the CF compartment door properly.

Double-check to make sure both the battery door and CF card doors are snapped shut completely.

CF card door closed properly?
Battery door closed properly?
Has it got wet recently?

Check both CF Card & Battery doors.
Both closed propertly.
Did not get wet.
thanks for the suggestions.
Do the on/off switches go bad??

Is the second battery - the little one that powers the camera's internal clock etc. - OK?

I don't know whether that would prevent the camera turning on, but removing the second battery seems to be recommended whenever one wants to "re-boot" a camera...

Is there a CF card in the slot?

I had that problem before and I slip a folded Postit on non contact side of the battery so that the battery will make contact to the camera. Check and make sure contacts inside the camera is clean.