Computer repair companies are usually on the cutting edge of technology. Being on the edge of technology brings with it a certain understanding of that technology that other people do not understand.
Computer repair companies must realize that they have knowledge that the general population does not have an understanding of the newest technology. That knowledge must be realized with business cards as well.
If you are crafting a new business card for your computer repair business, remember to use language that your target audience understands. 
Here are a couple examples:
Bad computer repair business card:
XYZ Computer is ISO-9000 compliant with ISAC Training for Windows 2003 servers and is Web 2.0 compliant and we design out web standards to be HTML, XHTML, XML, CSS, XSLT, and of course W3C compliant.
Something like that is going to be confusing to a majority of customers.
Good computer repair business card:
XYZ Computer has specialists that are certified in a variety of programs including web design, servers, Windows training and many other programs. Please contact us for a full list of standards and training programs we have expertise in.
This will allow you to reach your customers on a level of communication they understand!