[arch-general] Not able to do system updates

I don't know what happened, but overnight, my system doesn't seem to allow me to update or install packages. I tried with 'sudo pacman -Su' and with 'yaourt -Su' and nothing. I know of at least 10 packages that need to be updated from yesterday. And on further testing, I can't install new packages either. I want to try out the go-openoffice and oss packages, but it won't download. When I do an update though (yaourt -Sy), it does download the new package lists and the files in /var/lib/pacman are updated. Anything any of you might want me to try to figure this out, it'll be greatly appreciated. Thanks, Will