My cousin brother had bought a SATA DVD writer and he asked me to fix it to the system unit of his computer. My cousin is not an IT guy and so he didn't know what to consider before buying that. He had just gone to a computer shop and had bought the SATA DVD writer.
Before you buy a hard disk or a device like CD/DVD ROM/Writer, first you need to check what is the suitable type of it for example IDE or SATA.
I was not sure whether the motherboard had sata ports because it was a Pentium IV machine, so I checked it first. Fortunately it had sata ports.
Then I fixed the device to the Casing and connected the SATA data cable to the motherboard. Then I checked for the SATA power connector but the Power supply unit didn't have any but the IDE power connectors.
The only option left was to buy a Serial ATA Power Cable.It cost Rs. 150/= .
Serial ATA Power Cable
Connects any Serial ATA drive to a standard internal power connector.
After connecting this, it worked properly. So if you find such a problem, no need to replace the device or to buy another Power Supply Unit.