What does a technician need to check to determine if an additional hard drive can be added to an older computer?

To determine if an additional hard drive can be added to an older computer, checking for an available PATA/SATA connection is essential. This connection is the interface through which the hard drive communicates with the motherboard.

Older computers may use PATA (Parallel ATA) connections, while newer ones more commonly employ SATA (Serial ATA) connections. If there are no available connections for either PATA or SATA on the motherboard, it would not be possible to install another internal hard drive. This requirement is fundamental to ensure proper data transfer capabilities between the hard drive and the rest of the system.

Other options, while they may matter in specific contexts, are less relevant to the immediate need of installing an additional hard disk. A PCI slot is generally used for expansion cards rather than storage devices. USB ports facilitate external device connections and not internal hard drives. An available power supply connector is important and can be a limiting factor, but if the motherboard does not have the necessary interface connections, the hard drive still cannot be added irrespective of the power supply situation.