here is a trick
Step to make it
==> copy this (quoted) following code
==> open notepad
==>paste code
==>SAve the file with mp4.reg or whtever name u want but make sure itz extension is
.reg do c that whn the save option comes up , there u need to
save file as type do set it to "all files"
==> save the file and merge this file or simply double click..
ny problm pm me..
QUOTE
Windows Registry Editor Version 5.00
[HKEY_CLASSES_ROOT\.mp4]
"PerceivedType"="video"
"Content Type"="video/mp4"
[HKEY_CLASSES_ROOT\.m4v]
"PerceivedType"="video"
"Content Type"="video/mp4"
[HKEY_CLASSES_ROOT\.m4a]
"PerceivedType"="audio"
"Content Type"="audio/mp4"
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Multimedia\WMPlayer\MIME Types\video/mp4]
@="mp4file"
"UserApprovedOwning"="yes"
"Extensions.SpaceSep"=".mp4 .m4v"
"Extensions.CommaSep"="mp4,m4v"
"Extension.Key"=".mp4"
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Multimedia\WMPlayer\MIME Types\audio/mp4]
@="mp4file"
"UserApprovedOwning"="yes"
"Extensions.SpaceSep"=".m4a"
"Extensions.CommaSep"="m4a"
"Extension.Key"=".m4a"
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Multimedia\WMPlayer\Groups\Video\mp4]
@="mp4file"
"Description"="Includes files with .mp4 and .m4v extensions."
"Extensions"=".mp4 .m4v"
"FriendlyTypeName"="MPEG-4 Media File"
"MIME Types"="video/mp4"
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Multimedia\WMPlayer\Groups\Audio\m4a]
@="mp4file"
"Description"="Includes files with an .m4a extension."
"Extensions"=".m4a"
"FriendlyTypeName"="MPEG-4 Media File"
"MIME Types"="audio/mp4"
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Multimedia\WMPlayer\Extensions\.mp4]
"Permissions"=dword:0000000f
"UserApprovedOwning"="yes"
"Runtime"=dword:00000007
"PerceivedType"="video"
"MediaType.Description"="MPEG-4 Media File"
"Extension.Handler"="mp4file"
"Extension.MIME"="video/mp4"
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Multimedia\WMPlayer\Extensions\.m4v]
"Permissions"=dword:0000000f
"UserApprovedOwning"="yes"
"Runtime"=dword:00000007
"PerceivedType"="video"
"MediaType.Description"="MPEG-4 Media File"
"Extension.Handler"="mp4file"
"Extension.MIME"="video/mp4"