I haven't seen that issue before, but I really doubt it's fixable without a new motherboard. Whatever the differences are between USB1 and USB2, your motherboard doesn't like them.

The cheapest solution if you really need USB2 is to just buy a USB PCI card. They cost <$10 online.... well wait you're in Europe, but still. They are going to be a hell of a lot cheaper than trying to find a compatible motherboard. Does your Mom really need USB2?

It's really not uncommon to have different things fail on a motherboard. There's so many different things going on that you come to expect it. It's unfortunate but it's life.