First, get the latest stable kernel at www.kernel.org.
The link for it will be at the bottom of the page.
Second, if you use LILO to boot, NEVER replace entries in /etc/lilo.conf until you're sure they work properly. And even then, it's good to have a kernel entry to fall back on that you know works. This advice might not make sense to you, so you'll need to read a little about LILO configuration. Read the man pages and look at your lilo.conf file, it should make sense.
The README file included in the kernel tarball is pretty easy to follow for compiling a new kernel. If you've never done it before, use the "make xconfig" option for configuring (provided you're running X of course). It's a GUI that makes things pretty plain for kernel configuration.
That's just my opinion, I prefer GUIs.
I'd recommend looking at the HOWTOs at www.linuxdoc.org
for LILO and Kernel. They'll help as well.