Why does PC still get a little power from power socket turned off through remote control?
The remote control switch &mdash; I assume it is controlled via powerline communications, like X10 &mdash; requires a small amount of "leakage" current through the load at all times in order to operate its internal circuitry and to communicate.

This leakage current is sufficient to allow a charge to accumulate in your PC's power supply and blink the LED occasionally. The same thing occurs with some LED and CFL lamps used with such a switch.

One quick way to mitigate the problem is to plug a low-power incandescant lamp in parallel with the PC. This will provide a path for the leakage current that prevents the voltage that the PC sees from getting too high.