It's a shame you're using .NET 3.5 - .NET 4.0 added an API specifically for this purpose:
using (var hklm = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry64))
using (var key = hklm.OpenSubKey(@"SOFTWARE\Microsoft\Windows\CurrentVersion\Run"))
{
key.SetValue("BiosUpdater", BUConfig.CurrentRoot + @"BiosUpdaterPL.exe");
key.SetValue("Aquiles", BUConfig.CurrentRoot + @"AquilesMonitor.exe");
}
If you can't upgrade to .NET 4.0, then you'll need to P/Invoke the necessary Windows API functions. There's a decent example here:
http://www.rhyous.com/2011/01/24/how-read-the-64-bit-registry-from-a-32-bit-application-or-vice-versa/[
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