No, you cannot.
Read the thread on doing multiple things at once, it shows how to use millis() for timing instead of delay(). That's usually what people are looking for when they ask questions like this.
Also, it's not called a "void loop" - void loop() {...} defines a function named loop which returns void (ie, nothing).
Re led blinking thing - When a hardware reset (opening serial port or pressing reset button) occurs on an Arduino board, the LED will blink several times; this is done by the bootloader, which is what allows you to upload code via serial instead of ISP programmer. Is this the blink you're talking about?