make sure the following lines exist in the operating system registry. the absence of a single line indicates that the grand prix 4 is not installed or is not properly installed
the only difference you can find is in line for AUDIO (that in my PC is a sound blaster audigy)
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SOFTWARE\Infogrames]
[HKEY_LOCAL_MACHINE\SOFTWARE\Infogrames\Grand Prix 4]
[HKEY_LOCAL_MACHINE\SOFTWARE\Infogrames\Grand Prix 4\1.00]
[HKEY_LOCAL_MACHINE\SOFTWARE\Infogrames\Grand Prix 4\1.00\Install Dir]
"Directory"="C:\\Program Files\\Infogrames\\Grand Prix 4\\"
[HKEY_LOCAL_MACHINE\SOFTWARE\Infogrames\Grand Prix 4\1.00\Version]
"Number"=dword:00000066
[HKEY_LOCAL_MACHINE\SOFTWARE\Infogrames\Grand Prix 4\Audio]
"GUID"=hex:8f,f6,de,f4,07,e4,4d,57,a1,b0,d2,76,7c,af,8c,a4
"Desc"="Speakers (SB Audigy)"
"Module"="{0.0.0.00000000}.{8ff6def4-07e4-4d57-a1b0-d2767caf8ca4}"
"EAX"=hex:00
[HKEY_LOCAL_MACHINE\SOFTWARE\Infogrames\Grand Prix 4 Patch]
[HKEY_LOCAL_MACHINE\SOFTWARE\Infogrames\Grand Prix 4 Patch\1.00]
----signature--------------------------------------------------------
RELEASE => Physics (under FIA Technical Regulations)
MagicDatas? Setups? Pit Stop Strategies? Track Specific Performances? Up2Date GP?
Power Torque Curve? Where's this stuff? All download is available at ..