1. ms-dos 1981
2. windows 2.0 1987
3. windows xp 2001
4. mac os 2001
5. windows 7 2009
i think it would be the investment with high risk and high return such as Stocks.When
investing in stock, investor analyze whether a specific company will be
doing well in the time of investment (which will increase the market
price of the stock) and take a profit from it.
