Download large applications and they'll often come in the form of disc images, typically ISO files. To use these normally you'll have to burn them to CD or DVD first, then access the disc as usual. It's time-consuming, inconvenient, and costs you money if you're not using a rewriteable a disc, but there are alternatives. And PowerISO is one of the best.

At its simplest, you can use the program to mount the disk image as a virtual drive. It'll appear in Explorer just like any other drive, you'll be able to browse the image, launch setup programs, without the need to burn it to a physical CD.

PowerISO makes it just as easy to access virtual disk images for VMware (VMDK), Virtual PC (VHD) and VirtualBox (VDI) - simply open them, and browse their contents, edit individual documents, drag and drop files to or from the image and generally treat it just like any other drive.

But the program really comes into its own when you start creating your own images. Are you tired of software that won't run unless its disc is in your drive, for instance? Create an image, mount it to a virtual drive and put the real disc safely away: easy.

You can also create disc images with your own choice of files, make images bootable, password-protect or encrypt them, even compress them to save drive space, or reduce download time, if you're putting them online.

And perhaps best of all, PowerISO works with a huge range of image formats: ISO, DAA, BIN/ CUE, MDF/ MDS, IMG, NRG, CIF and others, more than 30 in total. Whatever images you come across, the program should be able to help.