Can do: "Apple was almost completely destroyed but it’s" .. "Apple was almost completely destroyed by its" - proofreading would catch "but/by". "It's" is a contraction for "it is". No apostrophe is needed.
"between today market situation and the past" .. "between today's market situation and the past" - "Today" is used as a possessive so it owns the "market situation". Ownership (in many cases) necessitates an apostrophe+"s". This is John's car. Tomorrow is Kate's birthday. It's a nuance that an ESL student can easily miss.
In fact, rereading your entire post I see many things that are rules that can easily be overlooked by ESL students.
Also, dashes ("-") should not be used for pauses unless they are being used for dramatic effect (someone will correct me on this and that's OK.) In every place where you used it (I count 4) it should either be replaced with a comma or eliminated.
"Apple announced it’s newest baby – game-changing device" .. "Apple announced its newest baby, a game-changing device"
"During the “PC war” there was a common platform for all the PC Clones – it was Microsoft DOS/Windows." .. "During the “PC war” Microsoft DOS/Windows was the common platform for all the PC clones."
"And here we are today – Apple is not afraid of competitors" .. "So here we are today. Apple is not afraid of competitors"
"we know it can be done – JQTouch anyone?" - OK
"write native apps for Android – instead they should reward" .. "write native apps for Android. Instead they should reward"
Just keep writing and practicing your skills.