Ubuntu 12.04 Realtime Kernel don't run

Hello everyone, sorry my english not so good !
I have a problem. I work at two years with Ubuntu 10.04 and Linuxcnc 2.3 without problems.
At last Time I have often little problems with the system stability, so I think I will make an update.
Yersterday I installed Ubuntu 12.04 with this guide.

wiki.linuxcnc.org/cgi-bin/wiki.pl?UpdatingTo2.6.

There was no Problem, after install I made a restart and test the system with uname -r and I see the Realtime Kernel don't run.

I try it again with

frank@PC-Frank:~$ sudo apt-get install linux-image-3.4-9-rtai-686-pae rtai-modules-3.4-9-rtai-686-pae
[sudo] password for frank:
Paketlisten werden gelesen... Fertig
Abhängigkeitsbaum wird aufgebaut
Statusinformationen werden eingelesen... Fertig
rtai-modules-3.4-9-rtai-686-pae ist schon die neueste Version.
linux-image-3.4-9-rtai-686-pae ist schon die neueste Version.
0 aktualisiert, 0 neu installiert, 0 zu entfernen und 46 nicht aktualisiert.

but the Kernel will not run.

frank@PC-Frank:~$ uname -a
Linux PC-Frank 3.13.0-32-generic #57~precise1-Ubuntu SMP Tue Jul 15 03:50:54 UTC 2014 i686 i686 i386 GNU/Linux

How can I activated the realtime Kernel.

Here are the boot folder

root@PC-Frank:/boot# ls -l
insgesamt 74456
-rw-r--r-- 1 root root 1166929 Jul 15 06:17 abi-3.13.0-32-generic
-rw-r--r-- 1 root root 805150 Aug 13 01:26 abi-3.2.0-68-generic-pae
-rw-r--r-- 1 root root 169741 Jul 15 06:17 config-3.13.0-32-generic
-rw-r--r-- 1 root root 147622 Aug 13 01:26 config-3.2.0-68-generic-pae
-rw-r--r-- 1 root root 134458 Jul 9 22:25 config-3.4-9-rtai-686-pae
drwxr-xr-x 3 root root 12288 Sep 11 21:03 grub
-rw-r--r-- 1 root root 18521645 Sep 11 19:25 initrd.img-3.13.0-32-generic
-rw-r--r-- 1 root root 19819142 Sep 11 19:24 initrd.img-3.2.0-68-generic-pae
-rw-r--r-- 1 root root 14671488 Sep 11 21:03 initrd.img-3.4-9-rtai-686-pae
-rw-r--r-- 1 root root 176764 Nov 27 2011 memtest86+.bin
-rw-r--r-- 1 root root 178944 Nov 27 2011 memtest86+_multiboot.bin
-rw

---

1 root root 2803199 Jul 15 06:17 System.map-3.13.0-32-generic
-rw

---

1 root root 2324059 Aug 13 01:26 System.map-3.2.0-68-generic-pae
-rw-r--r-- 1 root root 1437829 Jul 9 22:25 System.map-3.4-9-rtai-686-pae
-rw-r--r-- 1 root root 5919280 Aug 7 18:25 vmlinuz-3.13.0-32-generic
-rw

---

1 root root 5038496 Aug 13 01:26 vmlinuz-3.2.0-68-generic-pae
-rw-r--r-- 1 root root 2883072 Jul 9 22:25 vmlinuz-3.4-9-rtai-686-pae

What can I do ?
Do I need to change the Grub boot loader or the grub.cfg.
I am a Linux beginner.

Thanks for your help.

I am ashamed of that.
There is a submenu in Grub.

submenu "Previous Linux versions" {
menuentry 'Ubuntu, mit Linux 3.4-9-rtai-686-pae' --class ubuntu --class gnu-linux --class gnu --class os

I did not expect !!!

Now everything is running smoothly

Thx a Lot

Thanks for the information.
I have not yet dealt with the Grub configuration.
But I thought already that this is the way.

Thanks for the Link and thanks for the help.