Hi welcome to just answer.
Who is the manufacturer of the system? Can you check the model of the older remote if available.
There are a number of remote controls that I find outline that can work. Do you happen to have the model number of the remote or it is missing?
Can you take a picture of the back of the remove where there is a label, you might want to remove the battery covers and on the back of the cover, you will see the label.
ok. It seem not possible to find any remote for it. What is wrong with the existing remote? Have you tested it to verify its operation?
Does the screen light at least? If not, would you want to take it apart and look at the screen connection to PC board? The problem you are seeing is coming from dropping the remote. The contact with the screen becomes loose.