What switch can I use in my regtweaks to enable the option that puts the tick in the box to "hide known file extensions" under tools => folder options => view

This is the current set I have, maybe I've already got it here, but with wrong option selected:

;Configure Start Menu

[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced]

"Hidden"=dword:00000002

"ShowCompColor"=dword:00000001

"HideFileExt"=dword:00000000

"DontPrettyPath"=dword:00000000

"ShowInfoTip"=dword:00000001

"HideIcons"=dword:00000000

"MapNetDrvBtn"=dword:00000001

"WebView"=dword:00000001

"Filter"=dword:00000000

"SuperHidden"=dword:00000000

"SeparateProcess"=dword:00000000

"ListviewAlphaSelect"=dword:00000000

"ListviewShadow"=dword:00000001

"ListviewWatermark"=dword:00000000

"TaskbarAnimations"=dword:00000000

"StartMenuInit"=dword:00000002

"StartButtonBalloonTip"=dword:00000002

"Start_ShowNetPlaces"=dword:00000001

"Start_LargeMFUIcons"=dword:00000000

"Start_MinMFU"=dword:00000001

"Start_ShowControlPanel"=dword:00000001

"Start_EnableDragDrop"=dword:00000001

"StartMenuFavorites"=dword:00000002

"Start_ShowHelp"=dword:00000001

"Start_ShowMyComputer"=dword:00000001

"Start_ShowMyDocs"=dword:00000001

"Start_ShowMyMusic"=dword:00000001

"Start_ShowMyPics"=dword:00000001

"Start_ShowPrinters"=dword:00000001

"Start_ShowRun"=dword:00000001

"Start_ScrollPrograms"=dword:00000000

"Start_ShowSearch"=dword:00000001

"Start_ShowRecentDocs"=dword:00000002

"Start_AutoCascade"=dword:00000001

"Start_NotifyNewApps"=dword:00000000

ps.. I think it's this one >> "HideFileExt"=dword:00000000

which dword should I have.

Also, what option above is forcing my start menu to be the "classic start menu" and not the normal XP style start menu?

ps.. I think it's this one >> "HideFileExt"=dword:00000000

I think you are right

that should be dword:00000001

for the classic start menu, i'm taking a guess, try changing

"StartMenuInit"=dword:00000002

to dword:00000001 (honestly, I thought it was a different reg setting to change the start menu to classic)

Windows XP does hide known file extensions automatically, so you shouldn't be needing a tweak to do this.

he must have copied a registry tweak file from somewhere... because he already has a tweak turning it off

i like to make my own reg tweak files to avoid this sort of issue