I have Windows 10 on my computer, is this OK for running OpenCPN 4.4? Because I can't see the charts correctly. Will be waiting for you answer, thanks.
I've downloaded the latest version available on the homepage of the application and then I've installed it on Windows 10 x64. I also loaded a sample chart that I've found online and everything worked normally. There were no graphical issues or something that could prevent me from displaying the charts. Also the latest stable version is 4.0.0 Build 2015-01-08.
Try installing that and remove the current one from your computer. To download the application, use the following link: https://sourceforge.net/projects/opencpn/files/latest/download?source=files