Use a LiveCD like PartedMagic (http://www.partedmagic.com) with GParted available and use GParted to:
- Remove the Partition with 12.10 on it.
- Move the Partition called Softwares to the left (Don't know if this will change the drive Letter assigned to it in windows, so be sure you know how to assign drive letters to drives on windows if you have any programs installed to this partition)
- Grow the partition with 10.04 on it to fill the free space.
In order to repair your bootloader, you somehow have to boot your 10.04. I recommend using SuperGrubDisk 2 (available as standalone LiveCD on http://www.supergrubdisk.org and already integrated in PartedMagic). When you have successfully booted your Ubuntu 10.04, run the following commands to reinstall your bootloader:
sudo grub-install /dev/sda
Since you are messing around with both partitions and your bootsector, be sure to have a backup of all your important data as doing something wrong or having powerloss while partitioning may destroy your data and if in doubt, asking is better than walking into a catastrophy.