Thanks for all the help and advice.
After much hair pulling and gnashing of teeth I found the problem to be a conflict of resources which was solved by updating the ATi video driver! It seems to have fixed the problem, I should say, as Cubase now runs without crashing the system. It was the only application that caused this crash but I suppose that if it was trying to run the same resources as other parts… I’ve not yet had time to have a thorough audio session recording into Cubase except using VSTi and MIDI only.
I don’t run many VSTi currently. Most of the sounds I use are run through Halion Player - probably mostly up to 10 different sounds plus the drum sounds using Groove Agent which came with Cubase Studio 5.
I started to record audio (guitar double tracked on 2 channels) when the problems started. My ASIO settings were insufficient for the task but by increasing the buffer size from 512 up to 2048 has got rid of the stutter and crackle as this forum suggested somewhere. Interestingly, I started to use the ZOOM ASIOP as suggested in the manual but couldn’t change the buffer size from 512 at all. When I reverted back to the M-Audio Delta ASIO on the soundcard (Delta Audiophile 2496) it solved the problem.
I think that the Zoom R16 will probably be a good solution once I have got tamed! I have had it plugged in now for 7 days without any crashes! (Fingers crossed)
I am a real novice when it comes to recording audio. I have been using Cubase for many years running all the MIDI and recording guitars and voices, etc onto Yamaha AW16G. I needed to expand the number of tracks and as I had Cubase thought that it was the obvious route to go.
Biggest problem is, hopefully, short term - getting the sound I want using a new way of working - in Cubase as the master rather than the AW16G. Running effect channels and rediscovering compression settings for bass, lead and backing vox.
Thanks, again. I will definitely use this forum more!