Q: Bootcamp creates non-bootable partition

I have an old iMac, which has had its HDD replaced with an SSD. When I let the Bootcamp Assistant create a partition for installing Windows it does not work:

The partition is created, the system reboots, and then I'm told that there is no bootable device. When I check the new partition with Disk Utility it tells me that it is not bootable.

Can my problem be because of the SSD? What can I do to get round this? I've tried lots of things I found in different fora on the net but nothing works, mostly because I'm not allowed to di the proposed alterations to MBR, Bootcamp, etc, in spite of having the admin rights.

Any help is very welcome

  Model Name: iMac

  Model Identifier: iMac11,2

  Processor Name: Intel Core i5

  Processor Speed: 3,6 GHz

  Number of Processors: 1

  Total Number of Cores: 2

  L2 Cache (per Core): 256 KB

  L3 Cache: 4 MB

  Memory: 16 GB

  Processor Interconnect Speed: 6,4 GT/s

  Boot ROM Version: IM112.0057.B03

  SMC Version (system): 1.64f5

Physical Drive:

  Device Name: Samsung SSD 850 EVO 1TB

  Media Name: Samsung SSD 850 EVO 1TB Media

  Medium Type: SSD

  Protocol: SATA

  Internal: Yes

  Partition Map Type: GPT (GUID Partition Table)

  S.M.A.R.T. Status: Verified