Kernel messed up; unable to get internet access

I have apparently screwed up my kernel. When I boot the server using the CentOS 6 kernel (“CentOS 6 x64 vmlinuz-2.6.32-504.16.2.el6.x86_64” from the DO control panel), I get the following error and I’m not able to access the internet (it appears not networking):

FATAL: Could not load /lib/modules/2.6.32-504.12.2.el6.x84_64/modules.dep: No such file or directory.

(the directory /lib/modules/ is empty)

I’ve also tried using the DigitalOcean GrubLoader v0.2 (20160714) CentOS, which I only get the grub prompt. Grub doesn’t find any kernels in /boot/vmlinuz....

If I boot with the CentOS kernel, use console access and then run service network restart, I get the following errors:

Bringing up interface eth0: Device eth0 does not seem to be present, delaying initialization.
FATAL: Could not load /lib/modules/2.6.32-504.12.2.el6.x84_64/modules.dep: No such file or directory.

I believe the problem that caused this was removing old kernels (using rpm -e kernel-...), but it broke the kernel somehow (I think deleted it) as I wanted to get to the latest kernel with the meltdown/spectre fixes.

Any ideas how I can get a working kernel installed?

Let me know if you need any other details.