Can't register my dll

How can i register my XPCOM DLL to work for Netscape 7.0 ?
i tried copying my dll into components directory and also ran regxpcom.exe
but it doesn't work.
i created xpi which adds file into component and also placed ".autoreg" with
the exe but it still doesn't work.

When i left my DLL in the components dir and reinstalled Netscape 7.0, it
automatically detected it and worked fine.  anyway i want an installer which
installs my component and registers it and works fine.
any help would be appreciated.

Waqas