ubuntu server not booting; kernel panic

[MacNetron.ps]

I've had a power outage in the house (failure in the boiler, is fixed now) and now my server is not booting up anymore.
The rig is running Ubuntu Server 10 LTS.
The problem is, when I attach a monitor, that it fails fast with a kernel panic message.
I probably have had this issue too a year ago, and I recall that the source of the problem was that the server has installed some kernel updates and the booting process cannot find the appropriate kernel to boot anymore.

As I have forgotten , how do I
* get into the pre-boot screen to make sure the correct kernel is selected
* clean up and make sure this goes right without me manually doing stuff

[grom.ps]

Sorry - been incredibly busy during days and too knackered to do anything at nigh for a month or two so not been keeping up with the forum.

Anyway
you probably need to fix GRUB (this is the pre-boot screen you'll be talking about)
https://help.ubuntu.com/community/Boot-Repair should help - burn to cd or bootable USB stick