A program cannot locate a certain .dll file and won't run.?

You really should reinstall the program. Go to "Control Panel -> Add/Remove Programs" find your program and click install. Delete all the remaining program files. If you still have the setup file in the disk, delete it as well. Download the latest version of said program and install it. If you still insist in this version, try to find the ".exe" file. If the file you click is in your desktop, it's probably just a shortcut. You have to find the real "myprogram.exe" file, and put the .dll file in the same folder. Try it this way, should work. You could also try forcing the file inside. Inserting a dll into a running program is a very dangerous task. You have to use a program called "svchost.exe", it will host the dll into the target process. But it's highly recommended you do NOT do such. In my opinion, you should reinstall the whole program altogether.

oops there might be a problem that your program was infected by a virus and probably deleted by your anti virus thats why its not working properly.Ideally you should reinstall the program because this is a system file.

it could be malware, malwarebytes malware remover

perhaps you using demo version.

Just reinstall program.