I am wondering if anyone could help me.

My equipment/programs are admittedly old (equipment list below) but has worked perfectly for the last 7 years….until very recently….

Basically when I bring up my project, the Halion VSTt instrument (that I have previously, and successfully have been working on) works perfectly for about 10 seconds then the sound cuts out….

I know, and have checked that everything has been selected/routed correctly because I do get sound when I first open the project, sometimes it lasts for a couple of minutes but mostly it cuts out within seconds…

I can see the MIDI meter working when I hit the keys so again, I know everything is in place, and as mentioned everything has worked perfectly for the last 7 years…

The audio drop out to me makes no sense, and I was wandering if anyone had experienced this issue before, as you can imagine trying to work and finish a project is proving to impossible and very frustrating…!

Any help or advice would be greatly appreciated.
Many Thanks

Package: Cubase Studio 4
MacBookPro 2,2 - 10.6.8 -3 GB
Operting system: OSX
Audio interface: Focusrite Safire
Controller: M-Audio Oxygen 49 (silver)