Sample of needed entries that ensure reliable functionality are listed below (licence specific info stripped, that is still needed):

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion]

"DevicePath"=hex:25,00,53,00,79,00,73,00,74,00,65,00,6d,00,52,00,6f,00,6f,\

00,74,00,25,00,5c,00,69,00,6e,00,66,00,00,00

"FirstInstallDateTime"=hex:00,00,00,00

"SM_GamesName"="Games"

"ProgramFilesDir"="c:\\program files"

"CommonFilesDir"="c:\\program files\\common files"

"ProductId"= "NEEDS TO BE GRABBED FROM REAL WINDOWS"

"ProgramFilesPath"=hex:25,00,50,00,72,00,6f,00,67,00,72,00,61,00,6d,00,46,\

00,69,00,6c,00,65,00,73,00,25,00,00,00

"SM_AccessoriesName"="Accessories"

"PF_AccessoriesName"="Accessories"

"RegDone"="1"

"MediaPath"="c:\\windows\\media"

"OEMReset_Switch"=""

"RegisteredOrganisation"=""

"RegisteredOwner"=""

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Setup]
"DriverCachePath"=hex:25,00,53,00,79,00,73,00,74,00,65,00,6d,00,52,00,6f,00,\
6f,00,74,00,25,00,5c,00,44,00,72,00,69,00,76,00,65,00,72,00,20,00,43,00,61,\
00,63,00,68,00,65,00,00,00
"BootDir"="c:\\"
"PrivateHash"=hex:GET FROM REAL WINDOWS!
"CDInstall"=dword:00000000
"LogLevel"=dword:00000000 

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Setup\BaseWinOptions]

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Setup\ExceptionComponents]

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Setup\OC Manager]

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Setup\OC Manager\MasterInfs]

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Setup\OC Manager\Subcomponents]
"fax"=dword:00000000
"msmsgs"=dword:00000000
"rootautoupdate"=dword:00000000
"msnexplr"=dword:00000000
"autoupdate"=dword:00000000
"msmq_core"=dword:00000000
"msmq_localstorage"=dword:00000000
"msmq_triggersservice"=dword:00000000
"iis_common"=dword:00000000
"iis_inetmgr"=dword:00000000
"dtc"=dword:00000000
"com"=dword:00000000
"iis_www"=dword:00000000
"msmq_httpsupport"=dword:00000000
"msmq_adintegrated"=dword:00000000
"ieaccess"=dword:00000000
"iis_www_vdir_scripts"=dword:00000000
"iis_www_vdir_printers"=dword:00000000
"tswebclient"=dword:00000000
"iis_doc"=dword:00000000
"iis_ftp"=dword:00000000
"iis_smtp"=dword:00000000
"fp_extensions"=dword:00000000
"mswordpad"=dword:00000000
"calc"=dword:00000000
"charmap"=dword:00000000
"clipbook"=dword:00000000
"deskpaper"=dword:00000000
"mousepoint"=dword:00000000
"paint"=dword:00000000
"templates"=dword:00000000
"chat"=dword:00000000
"dialer"=dword:00000000
"hypertrm"=dword:00000000
"mplay"=dword:00000000
"rec"=dword:00000000
"vol"=dword:00000000
"accessopt"=dword:00000000
"pinball"=dword:00000000
"freecell"=dword:00000000
"hearts"=dword:00000000 
"minesweeper"=dword=00000000 
"solitaire"=dword:00000000
"spider"=dword:00000000
"zonegames"=dword:00000000
"indexsrv_system"=dword:00000000 
"wbem"=dword:00000000
"terminalserver"=dword:00000000
"snmp"=dword:00000000
"wbemsnmp"=dword:00000000
"simptcp"=dword:00000000
"upnp"=dword:00000000
"iprip"=dword:00000000
"lpdsvc"=dword:00000000
"display"=dword:00000000
"ntcomponents"=dword:00000000
"WMPOCM"=dword:00000000
"beacon"=dword:00000000
"OEAccess"=dword:00000000
"tpg"=dword:00000000 
"system"=dword:00000001
"oobe"=dword:00000001
"notebook"=dword:0000000
"stickynotes"=dword:00000000
"freestyle"=dword:00000000
"wmaccess"=dword:00000000
"netfx"=dword:00000000
"p2p"=dword:00000000

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Setup\OOBE]
"RunWelcomeProcess"=dword:00000000

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Setup\OOBE\CKPT]
"TOS"=dword:00000001
"0"=dword:00000003

[HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT]

[HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion]
"CurrentBuild"="1.511.1 () (Obsolete data - do not use)"
"InstallDate"=dword:00000000
"ProductName"="Microsoft Windows XP"
"RegDone"="1"
"RegisteredOrganisation"=""
"RegisteredOwner"=""
"SoftwareType"="SYSTEM"
"CSDVersion"=""
"CSDBuildNumber"="GET FROM REAL WINDOWS"
"CurrentVersion"="5.1"
"CurrentBuildNumber"="2600"
"SubVersionNumber"=""
"BuildLab"="GET FROM REAL WINDOWS"
"CurrentType"="Uniprocessor Free"
"SystemRoot"="c:\\windows"
"PathName"="c:\\windows"
"ProductId"="GET FROM REAL WINDOWS"
"DigitalProductId"=hex:GET FROM REAL WINDOWS

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\WPAEvents]
"OOBETimer"=hex:GET FROM REAL WINDOWS
"LastWPAEventLogged"=hex:GET FROM REAL WINDOWS

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Registration]
"ProductId"="GET FROM REAL WINDOWS"
"DigitalProductId"=hex:GET FROM REAL WINDOWS