At the moment I use a combination of large, bold fonts and an assistive technology application called ZoomText (http://www.aisquared.com/zoomtext/) to access the computer. ZoomText will magnify the screen contents and/or read them aloud to you; I use these features both independently and in combination. Other blind folks use straight-up screenreaders like JAWS (http://www.freedomscientific.com/products/fs/jaws-product-page.asp) or Window-Eyes (http://www.gwmicro.com/Window-Eyes/), which just read the screen to you without magnification. Still other folks use the newer Macs, which now come with screenreading and magnification right out of the box. Braille readers can also use refreshable braille displays (http://en.wikipedia.org/wiki/Refreshable_Braille_display), either alone or in combination with other assistive tech.

Hope that's helpful! :)