can a computer can be remotely started?

Question

you can use any thing like telephone line or any thing u thing is good

Answer 1

Yes, but you need an extra piece of equipment which starts the power to your computer. ~

Answer 2

Yes it is called wake on lan.

Wake on LAN (WoL) support is implemented in the motherboard of the computer. The motherboard must have a WAKEUP-LINK header onboard and connected to the network card via a special 3-pin cable; however, systems supporting the PCI 2.2 standard coupled with a PCI 2.2 compliant network adapter typically do not require a WoL cable as the required standby power is relayed through the PCI bus. Most modern motherboards with an embedded Ethernet controller also support WoL.


Wake on LAN must be enabled in the Power Management section of the motherboard's BIOS. It may also be necessary to configure the computer to reserve power for the network card when the system is shut down.

In addition, in order to get WoL to work it is sometimes required to flash this feature to the card. You can do this in Windows from the properties of the network card in the device manager, on the "Power Management" tab. Check "Only allow management stations to wake up the computer" to make sure it does not wake up on every single network activity that occurs. For Linux, there is a FAQ available concerning this issue.


[edit] How it works
The general process of waking a computer up remotely in a LAN can be explained thus:

The target computer is shut down, with power reserved for the network card. The network card listens for a specific packet, called the "Magic Packet". The Magic Packet is broadcast on the broadcast address for that particular subnet or the entire LAN. The listening computer receives this packet, checks it for the correct information, and then boots if the Magic Packet is valid.


[edit] Magic Packet
The Magic Packet is a broadcast frame, transmitted over port 0 (Historically the most common port used), or 7 or 9 (becoming the most common ports used). It can be sent over a variety of connectionless protocols (UDP, IPX) but UDP is most commonly used. The data that is contained in a Magic Packet is the defined constant as represented in hexadecimal: FF FF FF FF FF FF followed by sixteen repetitions of the target computer's MAC address, possibly followed by a four or six byte password.

Answer 3

If it supports "Wake on LAN" NIC technology, yes. Wake on LAN must be enabled in the Power Management section of the motherboard's BIOS. It may also be necessary to configure the computer to reserve power for the network card when the system is shut down.

Answer 4

Yes, if supported AND enabled in the BIOS.