i used this registry file and it worked fine:

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SOFTWARE\Bethesda Softworks]

[HKEY_LOCAL_MACHINE\SOFTWARE\Bethesda Softworks\Oblivion]
"Installed Path"="C:\\Games\\Oblivion\\"

[HKEY_LOCAL_MACHINE\SOFTWARE\Bethesda Softworks\Oblivion\1.00.0000]

[HKEY_LOCAL_MACHINE\SOFTWARE\Bethesda Softworks\Oblivion - Construction Set]

[HKEY_LOCAL_MACHINE\SOFTWARE\Bethesda Softworks\Oblivion - Construction Set\1.00.0000]



But the thing is its only for oblivion not knights of the nine or shivering isles!

How would i edit it so i can use them? Please help!