This worked. I used the source from the fourth slack 10 CD instead of this, because i was afraid that installing the newer driver might break the dependencies with the other alsa packages, and it worked.
Then I had a problem with nvidia. Every time i installed it for the one kernel, the installer would uninstall the previous installed driver including the module for the other kernel. I tried duplicating the source, reruning the .config and make dep for every kernel, but the installer insisted on this. I did not manage to install only the module (all the libraries of the driver besides the module are precompiled anyway). I managed to fix this by installing the the driver for the first kernel, then boot with the other kernel, move the hole modules directory of the first kernel to another directory, and reinstall the driver, so that the uninstall process of the nvidia installer wouldn't touch my precious nvidia.o module.
It was my first kernel compilation and it was pretty adventurous.
Thank you both for your help.