Ok. The motherboard appears to be Micro-ATX sized. But to check the size, can you measure it if you can?
If you have an M-ATX board, this means that you will be able to use a brand new Micro-ATX case with it if you are wanting have a case that’s similar size to yours and compact.
For your new case, what model were you going to buy?
Also, one last thing. Can I see the back of the PC? (Where the cables are plugged). I need to see if there is a separate I/O port (not built into the case) If you don’t have a separate I/O port, transferring it to a new case will result in a hole in the back.