First of all check that you set the turning power on from remote control in application settings: "Infrared RC" –> "Power control". Select the necessary power control method and set the power button.
Use remote control sensor only from the tuner package. With sensors of other tuners the power control function by remote may not work.
If you choose to use PCI bus PME line and PC doesn't turn on, check that PME function of PCI bus is enabled in BIOS setup. This BIOS option may look as "Wake up on PME", "Wake up on PCI" or something of this kind.
On some motherboards PC doesn't turns on from remote control when power is applied before first system start, if you select "Use PCI bus PME". This is because PCI controller is not yet programmed by BIOS for standby. Do not remove power from PC.
If you select emulation of ATX power-on button, check that you connected the cable from tuner package to Power-on connector of mainboard and to MB connector of tuner. The power-on button of ATX case must be reconnected to BTN connector of tuner.
Check the standby voltage of your power supply unit. Normally it must be 3.3 volts. Lower voltage may cause unstable work of power control function with high probability.
On some old mainboards standby power is not applied to PCI bus. In this case you'll be unable to use power control function.
PC may not awake by remote control from sleep mode in the case that main power is not removed from PCI slots. To remove main power you must select the sleep mode D3 instead of D1 in BIOS setup.