Unless I'm very much mistaken, you seem to have mis-understood what is required in installing a new kernel. You've only installed the source code for the new kernel, which doesn't actually do anything by itself. You need to compile that source code with the options you need to create a working kernel.
Googling for information on kernel compiling throws up tons of links for you to check, because re-compiling a kernel isn't the simplest of tasks. Though, you're usually quite safe if you remember to backup the old version and choose module for anything you're not sure about.