Most likely, your belt broke. If that's all that happened, then it shouldn't be too expensive. If something driven by the belt seized, and CAUSED the belt to fail, then it could get more expensive. Belt failure would cause all of the symptoms you described, as the belt runs the alternator (hence the power system message) and the power steering pump (no power steering.) I'm not sure if the V8 engines have water pumps that are run by the drive belt or the timing belt, but if it's the drive belt, that would also explain the fans running longer... hopefully, you didn't overheat the engine!
'98 Volvo S70 GLT-160k miles- my everyday driver. Mods: 16T turbo, injectors, ECU, TCU, wheels, and interior trim from a T5.
'02 Volvo XC70-120k miles- Wife's car
'90 Volvo 740GLE 16-valve wagon-218k miles- My workhorse car. Currently rebuilding the head because I'm the idiot who put off replacing his timing belt.
'88 Mercedes 190E 2.3- bought to fix up and sell, but I kinda like the little old beast, so I'm holding on to it for a little while.