[VERY URGENT] Change Registry Settings in Win7

[Shohag_ifas]

hi, i am using vb6. I made a program. And it need to change the specific registry value. Please see the attached module for registry events.

It works on winXP, but whenever i tried to win7 a error message said "Access Denied"

Here is the code :
SetStringValue "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon", "Shell", Chr(34) & "SampleText" & Chr(34)

Please some one help me out asap...
my project is 99.95% done, and i am stuck at this step.

So, i request you guys please help me out ASAP.

best regards
kamrul hassan