Questions – Is “You Alright?” (Without “Are”) Acceptable?

There are two phenomena in play in your examples. They are sometimes indistinguishable from each other:

• Was re-installing a workstation in a conference room;
• Discussed a quarterly report with X;
• Am on an expo in Chicago;

The first phenomenon is that of very informal speak, omitting the word subject I (and sometimes even the verb, as in my last two examples):

• Am on an expo in chicago.
• How are you? Am fine.
• Where are you going? On the way to the store.
• In a hurry, can't talk now.

Etc.

The other is the use of passive voice. This may be used in formal writing, or when describing something in general, without a specific subject in mind. The implied subject can be "we", "they," "I", "the boss," "the team," or anything else that fits the context. These sorts of things might be seen on an itinerary (in present or future tense), the minutes of a meeting or an executive summary (in past tense):

• (I|he|we|they) Discussed a quarterly report with X
• [Possibly] (I|he|the intern) Was re-installing a workstation in a conference room;
• (I will|we will|they will) Attend banquet.
• (I will|the students will) Receive awards.
• (I|the committee|the boss) Assigned tasks.

Since you are asking a question, the correct answer would be

Which one are you referring to?

Unless you phrased the question:

You are referring to which one?