[_delirium]

It depends on the language, but I haven't found that useful with Greek, unless you specifically want to learn the formal Greek words for computer-related things. In casual conversation, nobody uses that vocabulary, and it'd be seen as very stilted/old-fashioned (English loanwords are more common, and even where Greek's used, it's often not the same words).

[nodata]

But if you're in Greece and can speak and read Greek, but are then put in front of a Greek computer and can't use it, that looks pretty bad...

[_delirium]

Eh, I haven't found it to be a major problem. I speak fluent oral Greek (learned it when I was a kid to talk to my grandparents/cousins), and can read some Greek, but nobody really expects me to be able to read formal Greek. It's slightly diglossic in that formal Greek is substantially different than the spoken language, partly a relic of the days when it was an actually different language: http://en.wikipedia.org/wiki/Katharevousa