Recently I was trying to figure out if I could connect my old laptop which has VGA output to an Apple Cinema Display from a couple of years back that has a DVI-D connector/cable and I found out that you really cannot unless you buy a VGA-to-DVI-D converter.

Such a converter is not a simple adapter. Instead it is an analog-to-digital signal converter. Something like this.

Also from what I found on the Internet — you really want a very good converter since the digital signal requirements are very stringent. Unfortunately such converters are expensive $300 and up — for that price you can simply buy a new LCD monitor compatible with your laptop.