In kernel 2.6.xxx
u don't need to use:
make dep
The proper steps to compile kernel 2
1. make menuconfig/make oldconfig/make xconfig
2. make
3. make modules modules_install
4. Copy over ur kernel image to /boot and update ur bootmanager configuration. And reboot.
Lastly, after reading again ur problem, i see that ur kernel compilation is ok (just ur kernel options are wrong/ boot manager config is wrong)
Please double check. To not waste time and use a good and safe recommended options for .config for the kernel, get a config from slackware's .config for kernel configuration reference. I strongly recommend it.