Outlook Express Crashes on Send/Rec

[Plado]

I've searched all the microsoft help files on this and drawn a blank.
OE5 on a Windows 98 Sp2 has stopped dialling the internet when you click SEND/REC - and if you dial up yourself with a dial shortcut - Outlook then crashes when you click SEND/REC just hanging there needing a ctrl alt del to get out of it. It refuses to fetch mail or send any queued mail.

Tried all kinds of fixes and even upgraded to OE6 and IE6 with latest from MSoft. Now it will send and receive but still won't dial when you press SEND/REC though Internet Explorer will dial when you try to go to a URL when off line- up comes the dialler box and gives you the "connect" option. All settings look like they are correct and we tried Always dial my default and Dial when connection is not present; and never dial and none of them have the slightest effect.

I suspect a registry confusion but cleaning registry didn't fix.
One thing I didn't try was setting up a new Identity on OE and see if that also suffered from this.

I tried to Repair IE5 but was amazed to find there is no mention of either IE5 or OE5 in the Add Remove Programs list so I can't get at the Repair facility. This version of OE5 (before we upgraded it to 6) was supplied by some charity who provided it and I think the owner of the PC installed it over the top of the Outlook version that came with the PC when new.

I think it's a big mess but I haven't a clue where to look next on it.
Any ideas?