Actually, under vsfl ('volvo safety for life'), I think --let me know if I'm misinformed-- that ALL volvos of any age, regardless of whether you're the original owner, are covered for 1 free hour of diagnostics. This is something fairly new; it works well too because before they charged $100 to pull codes! But it works for them, too, because people who before would delay paying the $100, now get the codes read, and maybe end up paying for the work.
1999 is a watershed year; might be the older vadis, might be the newer vida-- someone else here ought to know.
Either way, stop by the dealer, 1 hour ought to be enough time, the codes they'll pull for free will give a much better sense of what's actually going on than most of us can tell you over a message board.
From the sheer number of things going on, a very uninformed guess on my part would be that some module, or maybe a wiring harness to a module, or a cem, etc., took a dump. If I had more experience, I'd have memorized what single point of failure might control all those systems, abs to power windows, but alas I don't know off hand
Once you know what and where you're going for, the forum should be able to talk you through the probable R&R if it's not just a software reset. Some of these electronics can be very expensive, and I half wonder if junkyard parts would be ill advised?
Also, once you find out what you need to do, DO call around. I was looking for a camshaft solenoid for a friend's 1999 volvo, and got quotes from $120 to $320 depending on the dealer and their markup. I'm not kidding. Who cares if you get some module from california or maine? They can ship it, probably.