Why are you so sure that it's alsa that's causing the problem? In the KDE settings menu for peripherals there's nothing about sound. There are options for infrared, monitor, mouse, keyboard, printer and digicam only. Maybe something else is wrong?
If you have an nvidia video card you need to install the drivers again.
Is your XF86Config-4 file still OK?
Can you get the error message x is giving. If lock solid doesn't mean you have to reboot you can see it, if not then there should be a log file in your /var/log folder.
BTW it would help if you told which distro you're using