When i reply or forward a message the text of the original message has disappeared - I would like the text of the original message to appear - how do I get back to this setting?

When I receive a message and want to reply or forward the text/message disappears - how can i re-set this so that the original text appears when i forward or reply to a message? == This happened == Every time Firefox opened == since I have had windows 7 on this new computer