Serial Port Blocked

I cant find my arduino leonardp COM port on device manager or in Arduino IDE.
I dont know what to do??!!
It was working b4 perfectly but now i have lost my COM Port anf I got this error mesg

processing.app.debug.RunnerException: Couldn’t find a Leonardo on the selected port. Check that you have the correct port selected. If it is correct, try pressing the board’s reset button after initiating the upload. at processing.app.debug.AvrdudeUploader.uploadViaBootloader(AvrdudeUploader.java:153) at processing.app.debug.AvrdudeUploader.uploadUsingPreferences(AvrdudeUploader.java:67) at processing.app.Sketch.upload(Sketch.java:1671) at processing.app.Sketch.exportApplet(Sketch.java:1627) at processing.app.Sketch.exportApplet(Sketch.java:1599) at processing.app.Editor$DefaultExportHandler.run(Editor.java:2380) at java.lang.Thread.run(Thread.java:619)

did you try to close and restart the IDE?

yes i did. I even restart the computer. but i still didnt find the Com port