Hi Dot:
Just a note about Thunderbird for you. As with Outlook and Outlook Express you can choose whether to have your mail sorted by date order, reverse date order, alphabetically by topic, alphabetically by sender, or whatever. All you need to do is to click on the relevant column heading. (e.g. if you want your emails listed with the most recent ones first, simply click on the 'Date' header until they appear in that order).
Chris
PS: Just how many emails have you got in your Inbox anyway? I've got a golden rule that my Inbox is always completely empty at the end of every day. I'd be annoyed with myself if I had an email from yesterday in there, yet alone from months ago!