'.' is not reconized as an internal or external command

after compiling the hello.c ,when i try to run it using ./a.out ,it says the following '.' is not recognized as an internal or external command,operable program or batch file. here are the system variables Path:C:\Windows\System32;C:\Windows;C:\Windows\System32\WindowsPowerShell\v1.0;C:\Program Files\Java\jdk1.7.0_71\bin;C:\apache-maven-3.2.5\bin;C:\Program Files\MinGW\bin;