That's a decent sound card - but very limited for music production as it doesn't have mic inputs, so you need to use a mixer. Latency will almost certainly mean a driver issue - check that Cubase is using the dedicated lynx driver and not one of the ASIO options - these are normally poor in latency terms.
Camn - I suspect is correct. Cubase 5 used a serial dongle and is elderly now, and the widely available cracked copies that get around the dongle are cracked by people who were not musicians, so while they make the main features work, quite a few of Cubase's less well known features involve a check of the dongle's presence - so you might look at the drum editor, and try to quantise and have Cubase crash on you. The versions after Cubase 5 started to have all the great soft synths, samplers and useful features - nobody with one of the latest cut down cheaper entry versions would ever want to go back to Version 5 - even if it was free. It's complicated to get your head around, there's no support and personally - I'd update to something better irrespective of the cracked version or a real one. I have a dongle still somewhere but I'd never want to even try to reinstall it. Things have moved on seriously since then.