Having this issue which seems fairly common. I've tried the suggested steps of deleting the system/tmp folder contents but it didn't help. The pycharm64.exe does not create a process in task manager, or output anything when launched from the terminal.
The only way to open pycharm is with the pycharm.bat file in the bin folder. Here is the output of that:
OpenJDK 64-Bit Server VM warning: Option UseConcMarkSweepGC was deprecated in version 9.0 and will likely be removed in a future release.
WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by com.intellij.ide.ClassUtilCore to field sun.net.www.protocol.jar.JarFileFactory.fileCache
WARNING: Please consider reporting this to the maintainers of com.intellij.ide.ClassUtilCore
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release