Messed up the partitions and the system

I have had Windows 8.1 Premium on my computer and wanted to go back to Windows 7 Home Premium because 8.1 did not seem to be working right.
When trying to download it I got the message that Windows 7 could not be installed on either of my partitions. When I tried to change the partitions or do anything with them, it refused.
Finally the computer just stopped trying to download or partition and now will not start.
It tells me to put in a recovery disk but all I have is the original and it says that is not the right one.
I am tempted to get out one of my old Ubuntu disks and try to partition with that one.
I am pretty sure that it is because the file systems are different but I don't know how to change it without a working operating system.
Any suggestions?
Thanks, Ken

You can try Acronis Disk Director Bootable media. Should do the trick quite nicely.

Acronis Disk Director 12: Download Bootable Media | Knowledge Base

Didn't understand what you're trying to do.
Did your computer came with Win 7 or 8?
When you mentioned download, did you mean downgrade?
Do you have a recovery disk? Is it Win 7 or 8?
Do you have a Data backup?

I do not have a recovery disk. I do have the original Windows 7 Home Professional dvd.
The computer came with Windows 7. I had that taken off and Windows 8.1 put on it. Windows 8.1 has taken me out of control on my Wifi so I decided to go back to Windows 7. I also had Ubuntu as a second operating system at one time but that was taken off when I had Windows 8 .1 put on it.
I hope this isn't too confusing.
The 8.1 apparently uses the new efi system and the Windows 7 used the old system so it won't install until I can reformat the hard drive.
@ WIN7 WINNN. I will have to see if I have $70 to put out for that program.
Thanks for the help. I will have to check things out in the morning as it is getting late at night here.

Simply boot seven install DVD when you get to the screen were it asks were to install there is an option to delete all partitions remove them all and let windows create what it needs

Thanks,
I will try that in the morning when I get up. I am upstairs now. I will close the thread if one of these works.
thanks again,
Ken

Win 7 can and should be installed on a UEFI - GPT disk.
On BIOS, Secure boot and fast boot must be disabled. CSM must be set to UEFI boot.

Backup all your data on an external disk as all data will be erased on the disk.
- Disconnect all other disks from the MB.
- Boot your Win 7 installation disk on UEFI mode (important), go to install - Advanced - delete all partitions - Install on the unallocated partition. Windows will create 3 partitions (UEFI - MS reserved - OS)