My advice is to quit monkeying around with it and take it to the dealer or a well equiped independent Volvo specialist. That car is first year network car so it could be anything and may very well require a software download to get it right again. On the same hand it could be something as simple as a loose or poor connection at the battery. If end up taking it to someplace that does not specialize in Volvos you might want to have them look at the red wire harness that goes from battery "+" to the main fuse box. The harness has a history of building up excessive resistance and creating volt drops that cause all kinds of funky problems. If your shop is not capable of measuring or interpreting volt drops it might be time to consider a new shop.

Mark