how to delete modules which are alredy uninstall? I have set of modules in my system but those modules are not properly un installed 
from the file system i have removed all modules but name aad path of the module still remains
in system table 

Any one please suggest me how to clear this garbage ?
Unless you disable and uninstall the custom modules you should not remove that custom module . This can cause performance and other issues. Get back those modules from backup. Then disable and uninstall them. Then you can remove the module.

There is even a module in Drupal 7 which will tell you deleted but not disabled modules which I'm not able to remember.