People with visual problems can now plug into and use any PC without having to download any special software they may require using a U3 key.

U3 keys are often called smart keys because they can hold software programs and settings, as well as data files. Because software remains on the U3 key and is not downloaded to a PC, not only does this open access to any computer, but it ensures privacy.

The host computer remains completely unaltered and the user has the full assurance that no personal information will be left behind.

A combination of FreedomBox Internet Suite and the System Access software that has been designed for these drives allows the visually impaired to use many mainstream applications.

System Access performs many of the functions of a screen reader. Because it taps directly into Microsoft's standard Windows controls via Microsoft Active Accessibility, it gives the user access to utilities and applications such as Microsoft Office, Notepad, Windows Media Player and Adobe Reader. It also lets users access VoIP service Skype .

FreedomBox offers internet access including web browsing, email, streaming media, and instant messaging. Users may also customise FreedomBox.

Steve Nutt, who is a blind computer technician, said for the first time he now has the flexibility to use any computer.

"I can now plug in this U3 key and help my customers with their computer problems because I can make the computer talk with this software," he told Computeractive.

The cost of the software, complete with a 1Gb U3 key is £382, but people who don’t need a key can download the software for £312 . Annual subscriptions then cost £70. PCs must have a USB port, a sound card and speakers, and must be running Windows XP.