You should use GUIDGEN.exe to create CLSID. found another article to create CLSID using regasm.exe but its not that true i guess. give a try.
regasm.exe /codebase /tlb whatever.dll
depending on your needs, /codebase or /tlb might not be needed (i.e. you can also try just regasm.exe whatever.dll).
To get the CLSID from GUIDGen.
Open Visual Studio-->Tools-> menu
select GUID select the Registry format as given in the pic
] press copy.