When I restart my PC my environment variables are deleted - windows

Question

My problem is that when I restart my pc my environment variables are lost. I encountered this problem with python libraries, I installed numpy and it worked, but after restarting my PC when I try to import it it gives me an error.
I now Facing this problem with DERBY,
This is my Installation:
C:\Users\ahmad>set DERBY_INSTALL=C:\Users\ahmad\db\db-derby-10.15.2.0-bin
C:\Users\ahmad>set CLASSPATH=%DERBY_INSTALL%\lib\derby.jar;%DERBY_INSTALL%\lib\derbytools.jar;%DERBY_INSTALL%\lib\derbyoptionaltools.jar;%DERBY_INSTALL%\lib\derbyshared.jar;.
C:\Users\ahmad> cd %DERBY_INSTALL%\bin
C:\Users\ahmad\db\db-derby-10.15.2.0-bin\bin>setEmbeddedCP.bat
C:\Users\ahmad\db\db-derby-10.15.2.0-bin\bin>SET DERBY_HOME=C:\Users\ahmad\db\DB-DER~1.0-B
C:\Users\ahmad\db\db-derby-10.15.2.0-bin\bin>set CLASSPATH=C:\Users\ahmad\db\DB-DER~1.0-B\lib\derbyshared.jar;C:\Users\ahmad\db\DB-DER~1.0-B\lib\derby.jar;C:\Users\ahmad\db\DB-DER~1.0-B\lib\derbytools.jar;C:\Users\ahmad\db\DB-DER~1.0-B/lib/derbyoptionaltools.jar;C:\Users\ahmad\db\db-derby-10.15.2.0-bin\lib\derby.jar;C:\Users\ahmad\db\db-derby-10.15.2.0-bin\lib\derbytools.jar;C:\Users\ahmad\db\db-derby-10.15.2.0-bin\lib\derbyoptionaltools.jar;C:\Users\ahmad\db\db-derby-10.15.2.0-bin\lib\derbyshared.jar;.
C:\Users\ahmad\db\db-derby-10.15.2.0-bin\bin>set MODULEPATH=C:\Users\ahmad\db\DB-DER~1.0-B\lib\derbyshared.jar;C:\Users\ahmad\db\DB-DER~1.0-B\lib\derby.jar;C:\Users\ahmad\db\DB-DER~1.0-B\lib\derbytools.jar;C:\Users\ahmad\db\DB-DER~1.0-B/lib/derbyoptionaltools.jar
C:\Users\ahmad\db\db-derby-10.15.2.0-bin\bin>java org.apache.derby.tools.sysinfo
------------------ Java Information ------------------
Java Version: 16.0.2
Java Vendor: Oracle Corporation
Java home: C:\Program Files\Java\jdk-16.0.2
Java classpath: C:\Users\ahmad\db\DB-DER~1.0-B\lib\derbyshared.jar;C:\Users\ahmad\db\DB-DER~1.0-B\lib\derby.jar;C:\Users\ahmad\db\DB-DER~1.0-B\lib\derbytools.jar;C:\Users\ahmad\db\DB-DER~1.0-B/lib/derbyoptionaltools.jar;C:\Users\ahmad\db\db-derby-10.15.2.0-bin\lib\derby.jar;C:\Users\ahmad\db\db-derby-10.15.2.0-bin\lib\derbytools.jar;C:\Users\ahmad\db\db-derby-10.15.2.0-bin\lib\derbyoptionaltools.jar;C:\Users\ahmad\db\db-derby-10.15.2.0-bin\lib\derbyshared.jar;.
OS name: Windows 10
OS architecture: amd64
OS version: 10.0
Java user name: Ahmad
Java user home: C:\Users\ahmad
Java user dir: C:\Users\ahmad\db\db-derby-10.15.2.0-bin\bin
java.specification.name: Java Platform API Specification
java.specification.version: 16
java.runtime.version: 16.0.2+7-67
--------- Derby Information --------
[C:\Users\ahmad\db\db-derby-10.15.2.0-bin\lib\derby.jar] 10.15.2.0 - (1873585)
[C:\Users\ahmad\db\db-derby-10.15.2.0-bin\lib\derbytools.jar] 10.15.2.0 - (1873585)
[C:\Users\ahmad\db\db-derby-10.15.2.0-bin\lib\derbynet.jar] 10.15.2.0 - (1873585)
[C:\Users\ahmad\db\db-derby-10.15.2.0-bin\lib\derbyclient.jar] 10.15.2.0 - (1873585)
[C:\Users\ahmad\db\db-derby-10.15.2.0-bin\lib\derbyshared.jar] 10.15.2.0 - (1873585)
[C:\Users\ahmad\db\db-derby-10.15.2.0-bin\lib\derbyoptionaltools.jar] 10.15.2.0 - (1873585)
------------------------------------------------------
----------------- Locale Information -----------------
Current Locale : [English/United States [en_US]]
Found support for locale: [cs]
version: 10.15.2.0 - (1873585)
Found support for locale: [de_DE]
version: 10.15.2.0 - (1873585)
Found support for locale: [es]
version: 10.15.2.0 - (1873585)
Found support for locale: [fr]
version: 10.15.2.0 - (1873585)
Found support for locale: [hu]
version: 10.15.2.0 - (1873585)
Found support for locale: [it]
version: 10.15.2.0 - (1873585)
Found support for locale: [ja_JP]
version: 10.15.2.0 - (1873585)
Found support for locale: [ko_KR]
version: 10.15.2.0 - (1873585)
Found support for locale: [pl]
version: 10.15.2.0 - (1873585)
Found support for locale: [pt_BR]
version: 10.15.2.0 - (1873585)
Found support for locale: [ru]
version: 10.15.2.0 - (1873585)
Found support for locale: [zh_CN]
version: 10.15.2.0 - (1873585)
Found support for locale: [zh_TW]
version: 10.15.2.0 - (1873585)
------------------------------------------------------
------------------------------------------------------
now I will restart my PC:
C:\Users\ahmad>echo %CLASSPATH%
%CLASSPATH%
C:\Users\ahmad>cd %DERBY_INSTALL%\bin
The system cannot find the path specified.
C:\Users\ahmad>java org.apache.derby.tools.sysinfo
Error: Could not find or load main class org.apache.derby.tools.sysinfo
Caused by: java.lang.ClassNotFoundException: org.apache.derby.tools.sysinfo
C:\Users\ahmad>cd db
C:\Users\ahmad\db>cd db-derby-10.15.2.0-bin
C:\Users\ahmad\db\db-derby-10.15.2.0-bin>java org.apache.derby.tools.sysinfo
Error: Could not find or load main class org.apache.derby.tools.sysinfo
Caused by: java.lang.ClassNotFoundException: org.apache.derby.tools.sysinfo
this is the result, it seems like my PC don't save what I do in the CMD.
Now I noticed I don't even need to restart it, even if I closed the current CMD and opened another one, it won't work.
Any Help?