Dropping out/Freezing/Crashing

I am producing a fairly simple song with five audio instruments and one MIDI one. There are only a couple of FX and I am not using V Vocal or Audio Snap.
Until recently it had played through and recorded all according to plan, then without any alterations to settings by me it has decided to freeze/drop out at the same point in the outro every time leaving me with a milky, semi opaque screen that I have no control over, other than Ctrl+Alt+Del.
The tracks all play well up to the crash point and after re-loading, they play well from a couple of beats after it, through to the end. Other songs play normally all the way through.
Does anyone have any suggestions please, as I an unable to finish the song if things stay the same?
wm0203

Thanks for replying chefmike8888.
I have tried what you said, but no luck.
An interesting thing I found was that it still froze at the same point, even if I was playing the song with no tracks soloed, i.e. a silent playback.
wm0203