Note: I won't show any fixes in this post. This is my farewell to Arch.
I did a full upgrade of my Arch system (amd athlon II x3 with an nvidia gf210 card) earlier today. Among the packages was kernel 3.10-2 (I think).
Turning on the computer this evening I'd get to the gdm log in screen -- with an unresponsive keyboard and mouse. I also can't log in via ssh from another computer, so the network seems not to work.
I can, however, boot using the fallback option in grub. The network still isn't working though. I use wicd. If I try to connect using wicd the system freezes and crashes.
The closest I can find is this: https://bbs.archlinux.org/viewtopic.php?id=167090 -- but I use BIOS, not EFI. And there are plenty of other differences. It does, however, seem to have to do with the new kernel.
And systemd makes troubleshooting this worse than necessary since the logs are binary. Seriously, the use of plain text files in linux for configuration and logs is one of the MAIN defining features of the OS.
Anyway, Arch is a fine OS. But I've been burned a few times too many now, and I am no longer young and have plenty of time and enthusiasm for this kind of stuff. I've just started installing debian instead...and for once I'm going straight for stable...
A contributing factor is that we use this computer as the family one, for watching tv, listening to music etc. And sitting down on a Sunday evening to relax and finding that the damned system won't even boot isn't a good way to end the weekend.
Anyway, if you are looking for a fix, all I can give you is my gut feeling -- downgrade. The old packages are in /var/cache/pacman/pkg
Otherwise, if you have a copy of the kernel sources, compile your own kernel and install it as shown e.g. here:
Why downloading the source and copying it? Because (imho) it's easier than fiddling with packages -- you can put the sources on a usb stick and copy it. But good luck, whatever method you try. I'm switching my second to last non-debian computer back to my main OS (i.e. debian). I've still got a Scientific Linux box, which I haven't booted for well over a month now...
It's 'funny' this should come less than 24 hours after me nit-picking about the use of 'stable' to describe Arch...http://news.softpedia.com/news/Arch-Linux-Is-the-First-Stable-Distro-with-Linux-Kernel-3-10-371457.shtml