Whats stopping my vista computer going into sleep (S3)?
This is usually caused by a piece of hardware that isn’t going to sleep properly. Usually because of poorly-designed drivers. Bluetooth adapters are pretty bad offenders for this. See what happens if you remove it before putting the PC to sleep. Also try removing the TV tuner again and testing it. TV tuners can sometimes cause problems, because they have the ability to wake the PC up from sleep mode (usually to start recording programs automatically). There is somewhere in the power options the ability do disable waking up from sleep by PCI devices. Make sure this is disabled and see what happens.
