Here are some guidelines and tips for shopping for a new computer if you are blind or visually impaired. These tips are tailored toward people who will be using assistive technology on their computers.

Memory: At least 2 gigabytes. Screen readers take up memory, not to mention other software that hogs memory like digital music editing software.

Hard Disk: Minimum size: 80 gigabytes; hard disks are cheap, programs continue to get larger and larger. 80 gigabytes will allow you to store thousands of MP3 files, and many more text or word processor files.

Processor Speed: Computer salespeople hype this too much. The typical user does not need the fastest computer on the market. 1.6 GHz is fast enough.

Operating System: Microsoft released Windows Vista in January 2007, and screen readers and screen magnifiers are currently available. Windows XP professional is still a viable option, if you can find it. VoiceOver, from Apple, is the only current screen reader for the Apple Macintosh. Very few people who are blind or visually impaired use Macintoshes.

Video System: Get at least 64 megabytes of video memory.

Sound Card: Buy a sound card that is capable of playing sounds from multiple sources such as the Sound Blaster Live from Creative Labs. This will let you use one of the software synthesizers, Eloquence for example, that are included when you purchase a screen reader, and listen to audio over the Internet at the same time.

Mass Storage: Include a built-in CD-rewritable drive. This will allow you to back up your files—CDs hold up to 650 megabytes of data.

Ports and Slots: USB ports are standard now. Make sure the computer you buy has several USB ports. Serial ports have disappeared from current computers. Many assistive technology devices used to use serial connections. You can purchase USB-to-serial converters.

If you are planning to buy computer online, be sure to read the product description, reviews and  read  13 Top Security Tips for online shopping.