What capacities of hard drive offer the best value for money?

Hard disk drives with a relatively modest 200GB to 300GB of storage space are still plentiful on retailers' shelves but, if you're going to upgrade your system with a new hard drive, you can get a 500GB drive for little extra cash.

The biggest price drop over the last few months has been in 1TB (1,000GB) drives, which now offer the most space for your money.

What different interfaces are available?

Older PCs use the IDE/UDMA interface standard for connecting internal hard drives, while SCSI has always been far less common in PCs than in Macs.

More recently, the much faster SATA (Serial ATA) standard has taken over and most of the latest hard drives are built to this specification.

What if my PC doesn't have SATA?

If you want to take advantage of the higher speeds and capacities offered by the latest hard drives, but your PC doesn't have SATA built in, the good news is that you can buy a plug-in card that mounts into a spare PCI slot and provides an SATA interface for both internal and external hard drives.

These tend to cost between £15 and £30 and are quite easy to fit and to set up.

Is it easy to fit a second hard drive?

Whatever connection standard you're using, it's a good idea to leave your existing hard drive in your PC (if it's still working ok) and to fit a second hard drive in addition.

Most desktop PC cases and pretty much every mini-tower or tower design cater to having two hard drives fitted.

Consequently, you can add extra storage capacity and fit the drive without having to re-install Windows and all your programs, as well as copying all your data across.