First, complaints that the Ubuntu installer "doesn't detect Windows" often mean that you need to use the "something else" installation option, which enables you to do manual partitioning. See this question and its answers for details.
That said, your problem likely requires doing more than this, or at least something different. The screen shot you showed indicates that you have four primary partitions on your first disk. An MBR disk, which that one is, can handle a maximum of either four primary partitions or three primary partitions and one extended partition, which can then hold as many logical partitions as you like. This is a limitation of the hackish MBR scheme.
Given that you already have four primary partitions, you have basically two options:
- Delete a partition -- You can delete a partition, which will then make room for either one primary Ubuntu partition or an extended partition, which can hold as many logical partitions as you like. The latter is the better choice.
- Convert one or more partitions from primary to logical form -- You can use a tool like
fixparts (which comes with Ubuntu) to convert one partition from primary to logical form. It looks like your D: partition would be a good candidate for conversion, but it could be that I'm missing something. Once the partition is converted, you can add logical partitions immediately before or after the converted partition. (All logical partitions must fit within a single extended partition; you can't put primary partitions in a run of logical partitions.)
I don't know what's on your partitions, so I don't know if you could delete one of them. If not, converting one to logical form is likely to be your only choice. As I said, fixparts can do this. So can some Windows tools. I think this includes the EaseUS tool that you're using, but I'm not 100% positive of that, and if it can do the job, I can't give you step-by-step instructions for how to do it. There are caveats and risks to doing a primary-to-logical conversion. Most notably, you must be sure that you don't convert a Windows boot partition, since Windows insists on booting from a primary partition. The fixparts documentation covers this subject in detail. (Disclaimer: I wrote fixparts.)
(Actually, there might be one other approach, but only if your computer has EFI firmware. This would involve converting Windows to boot in EFI mode and the disk from MBR to GPT form. This Microsoft tool can do so, or so they say -- I've never tried it myself. This approach is likely to be much harder than converting one partition from primary to logical form, and it will work only on EFI-based computers. Most computers sold since late 2011 have EFI firmware, but most older computers are BIOS-only. A Windows 7 system could have come with either type of firmware.)
