Hi,
hooising, and welcome to the forums.
First off, your picture is very very large, but the actual relevant part is tiny, too tiny in fact to see well. Follow
How to use the Snipping Tool in Vista to use the snipping tool correctly to make image posting a lot easier and a lot more readable.
According to the picture, it looks like you have made the digital TOSLINK as the default - change that.
And as for memory, well, Vista *does* have a virtual memory system in place....so, usually, no, and especially not before giving you multiple warnings about being low on memory. However, if one of your memory DIMMs fails while in use it could very well lead to a BSOD and a reboot....