I assume, from your post, that your ISP and e-mail provider is Orange.
First, check that Outlook Express hasn't 'lost' the relevant settings. (OE has a nasty habit of doing so!).
Open Outlook Express. Go to Tools > Accounts > Mail. You should see your account listed in the box. If it's not already highlighted, click on the account name to highlight it. Then select 'Properties'. Work through the tabs and check that the information matches that shown here:
http://help.orange.co.uk/documentDisplay.do?cl usterName=DefaultCluster&preview=1&groupId=1&p age=http://ESERVER_8ab88f64-4f52-4c74-b43a-fcd 25512ad40.xhtml&docType=1006&resultType=5002&d ocProp=$solution_id&docPropValue=kb15463
If you need to change anything, do so, then click 'Apply' followed by 'OK'.
Another possible cause of the problem is that Zone Alarm might not be allowing OE to access the internet. Click on the Zone Alarm window, which should be minimized at the bottom of your screen. Then click on 'Program Controls' & 'Programs'. Outlook Express should be listed, with two green ticks alongside it, in the 'Access' column. If there's a red cross, click on it and change it to a tick.
Chris