Cubase 5.1 problems

Just got 5.1 and am trying it out . XP Pro SP3 and a old crappy but does the
job soundblaster live.

Been using SX3 for a while and the current ASIO4all drivers without
problems. Have imported a simple 3 midi track song using VSTi for sounds
into 5.1 and there is no sound but the tracks section shows midi activity on
all tracks but the transport bar shows nothing.

Went into device setup and changed the Asio4all driver to Asio DirectX full
Duplex and it now plays with sound, but now the input latency is around
300ms so its unuseable except for playback.

Anyone have any ideas on this, i cant find anything to suggest the ASIO4all
shouldnt work with 5.1.

The second problem might be to do with the first one, there is a big drop in
volume levels using 5.1 compared to SX3 playing the same file, using the
transport volume slider on full its still barely acceptable. If i play the
song in SX3 shut it down and open 5.1 its like half the volume even though
nothing has been altered. The only way to achieve the same volume is by
raising the pc speaker volume to nearly max.

I have never had volume probs with SX3 or any other version, far from it in
fact i'm always turning levels and volumes down just 5.1

Any clues

thanks for any help you can offer