Normally with a cabled network connection you just plug and go. The fact that you can even start to download web pages suggests you have a connection.
You say you got various error messages with OE. Without knowing what the errors are, impossible to make suggestions. If email accounts are gmail, google have introduced a block on using the likes of OE and Thunderbird - you have to go online (e.g. via webmail) to remove the block.
Old backup PC? How old? Could just be a very underpowered PC (by today's standards) and seem slow compared with what one is used to. Plus webpages now are much much richer in content (than in times of yore) and so will take longer to process (on an old PC).
Also, if you've just turned on a PC that hasn't been used for a while / long time it may be trying to do all sorts of updates in the background as well.
Soit dit en passant, pas une bonne idée d'utiliser un nom d'utilisateur qui vous rend si facilement identifiable (en supposant que ce est le cas).