OEL 5.3 guest wouldn't boot after installing 11gR2 grid - fixed

Question

Ran into this twice so I thought I'd post it:
- standard OEL 5.3 64bit template
- Using the public Oracle yum repo and install the unixODBC pkgs and possibly a couple others that the installer is looking for.
- Configure ASM via manually adding a storage volume, fdisk'ing it, udev'ing it and "service oracleasm configure" - ASM is happy, installer sees the ASM storage
- runInstaller using the 11.2.0.1 11gR2-GridInfrastruture.zip downloaded from Oracle
- Installer does it's thing, no errors. +ASM  is up and running just fine.
- reboot - not so much - grub is pointing to a non-existant kernel. OVS blows this (confusing) error:
>
Start - /OVS/running_pool/66_cnvdb01
PowerOn Failed : Result - failed:<Exception: return=>failed:<Exception: ['xm', 'create', '/var/ovs/mount/42B0519525064CA2B952462BEC0C206E/running_pool/66_cnvdb01/vm.cfg'] => Error: Boot loader didn't return any data!
StackTrace:
File "/opt/ovs-agent-2.3/OVSXXenVM.py", line 57, in xen_start_vm
run_cmd(args=cmd)
File "/opt/ovs-agent-2.3/OVSCommons.py", line 85, in run_cmd
raise Exception('%s => %s' % (cmdlist, p.childerr.read()))
StackTrace:
File "/opt/ovs-agent-2.3/OVSSiteVM.py", line 131, in start_vm
raise e
>
Fix for me is: Do this on the host -->
mkdir /x
mount -t ext3 -o loop,rw,offset=32256 /OVS/running_pool/<xx_broken_guest>/System.img /x
cd /x/grub
ls -la grub*
mv grub.conf grub.conf-bad
cp grub.conf.orabackup grub.conf
cd /
umount /x
Then you can startup the guest. You can do it manually if you want to watch it by -->
xm create -c /OVS/running_pool/66_cnvdb01/vm.cfg

Answer 1

The lights/fans powering up for a split second and going back out every time you try to turn the PC on = PSU going in to protection mode due to a fault or short, most likely in the board.
Given MSI's track record lately, I would bet you fried at least one of the MOSFETs...this is a common problem on the 890fx they're producing, not sure if it is happening with their other models.  Unplug the 4 or 8pin cpu power from the board and hit the power button.  System won't boot, but the lights/fans should come on.  If they do, the MOSFETs are junk and you'll need a new board.
Another possibility is you are grounding out the board somewhere it shouldn't be grounded.  Remove the board, check the back of it and make sure it is not contacting the case anywhere.  Check all the board standoffs to make sure they are mounted securely to the case, check all the board mounting screws to make sure they are threading in to the standoffs correctly and that you didn't overtighten any and damage the board.
The "flicker" is usually one of the above issues, but could also be a bad PSU, bad CPU, bad RAM, etc.  You could try booting with one stick of RAM at a time, without the video card, etc, try to use a process-of-elimination to figure out what the faulty part is.  If installing the new cooler caused this, the problem would have likely shown itself right away instead of waiting a day or two.