A tricky question to answer for numerous reasons, primarily the possibility that the correct question might well have asked how long it would take Stavros to kill
Linguo. That written, all things Stavros are perpetually a mystery, so I'll go at this one a few different ways…
Answer 1: For Stavros to kill Linguo (the grammar robot) the only hope Stavros really has is time, seeing as there's little chance he could kill Linguo via grammar related means. If Stavros could wear Linguo's power reserves down to the point of decreased mobility, there's a chance he

could enlist Appolonia to crush Linguo (if that even counts). To provide more depth to this answer, I've included a photo of Appolonia, taken on January 26, 1998, to give a sense of her crushing power.
It will come as little surprise that Appolonia did not make the casting cut for
Stripsearch: Waikiki.
I'd conservatively estimate that for this sort of
death, it would take Stavros roughly two years to kill off Linguo, and likely even longer in the event Appolonia lost weight and needs to reestablish her crushing mass. As an alternate means of killing Linguo, he could be fruit-flied to death, although the more probable scenario is dragging Linguo along to what we here at the Ask Gary Blog like to call "An Afternoon with the Sozas." Turns out that Linguo can't function well when contained inside areas shielded by tinfoil window coverings. This would lead to a exceptionally short death sequence, provided of course Ney wasn't responsible for getting either Stavros or Linguo to the Soza's in the first place.

Answer 2: On the off chance the question was written correctly, and is in fact referring to
Lingo, the longest running game show on GSN, that will obviously require a far different tactic, although once again it all comes back to Ney. Why? Because Ney's former roommate (not Zach) is an executive at GSN. If Stavros has some sort of leverage (which is entirely plausible given the many Stavros related events that transpired at the Orange Grove house) than he might be able to wield that in an effort to force the former roommate to drop
Lingo from the GSN schedule. All told, this could take six to nine months to enact.
Answer 3: Lastly, in the event the original question was regarding Stavros' ability to kill off
Lingo, the programming scripting language used in Macromedia Director, my initial research suggests that Lingo is a formidable foe. Having existed in numerous incarnations and written by many software publishers, Lingo has taken on many forms ranging from a high level programming language for Windows, a Lisp based programming language for Recursiv CPUs, and shockingly enough, even a programming language for solving linear, nonlinear and integer optimization problems.
It's highly unlikely that Stavros could find a way to eradicate all these Lingo variations, this becomes increasingly true when you examine his current computing resources, a dated Mac PowerBook running Mac OS X 10.2. I suppose it's theoretically possible that Stavros could contract with some rogue programmers to create a global-Lingo-killing virus, which could take several years to write, and honestly, I just don't envision him having the focus to pull that off.
Enjoy.....................G