I am unable to install over the top of my 32bit ubuntu 12.04 successfully. I start out with win7 64bit and ubuntu 12.04 32 bit installed and working/booting without a problem . I decided to go to ubuntu 64 because of issues i was having with nvidia and xorg stuff.
First I backed up my C drive using acronis true image 2013, so i could start over (as i have had to do everytime).
My C drive (an intel ssd 80gb drive) looks like this before i attempt the 32 to 64 ubuntu install.
sda1 100MB boot partition
sda2 55GB NTFS Windows 7 install directory
sda3 5.5GB ext4 / (root)
sda4 8.2GB ext4 home
The swap file for ubuntu is on a different drive and so is the windows page file.
My system is a core i7 950 with 12gb ram so i havent actually ever exploited paging.
When i boot to a 12.04 64 bit DVD , I try the first choice (delete ubuntu and reinstall), i get a message saying the size of the partition for ' ' should be 2.4 or larger, and that i should change it be that size at least.
When i boot to 12.04 64 bit DVD, and try the last choice (something else) , and then i just specify to format the 5.5gb partiton and make it "/" as mount point and format it. Also i specify to use the 8.2GB drive as /home (no format). I run the install but when i restart i get an error saying the UUID is not found and grub prompt....ugh!!!
I then used Acronis started over. everything back to functioning with 32bit..
Tried boot to 12.04bit DVD, again try last choice (something else), and then i play with the boot disk parm .. no matter what i do i get the UUID not found and a grub promt...
In both cases i can PF12 and tell the system to boot from my hard drive and I get the grub menu and can go into ubunto , but if choose the windows install it redisplay the grub menu.
Seems like MBR is screwed up in all cases, not sure where i can go from here.
Reinstall from acronis backup and ????
Have gotten nowhere on this.