Answer:
No, they are different punctuation marks and they have different uses.
A colon ( : ) should always be preceded by a complete sentence, and it is sometimes used instead of a period. There are two ways to use a colon:
1. To set off an illustration of a point. For example:
The girl was tired of the game: she'd been playing it all day.
You could use a period here, but a colon helps link the two thoughts. The second short sentence is directly illustrative of why the girl was tired, so it provides further clarification. The colon is stronger than a period when it comes to showing a cause and effect relationship. In the case above, the second portion is a complete thought, but it's dependent on the first sentence for meaning.
2. A colon can set off a list: For example:
My car was packed to the roof with sporting equipment: tennis rackets, soccer balls, baseball bats, and a surfboard.
Here, the portion after the colon is not a complete sentence: it is dependent on the first half of the sentence (note how in this very sentence I've used a colon to set off further description of why it is not a complete sentence!). However, the first portion IS a complete sentence. Thus, you could not write it like this:
My car was packed to the roof with sporting equipment including: a tennis racket, ....
In that case, the first portion is not a complete sentence.
3. In academic writing a colon is used before an indented quotation. For example: As Weinstein (1999, p. 140) notes, this view presents problems:
[Indented quotation]
A semi-colon ( ; ) is used to link two complete sentences. Note that. They must both be complete thoughts. Anywhere you use a semi colon, you should be able to use a period as well.
You typically use a semi colon to link two thoughts without using a conjunction. For example:
I have to get gas in my car; I'm going to Banff this weekend and it's a long trip.
There is a second use of a semi colon, and that is to set off items in a list where there are already commas present. Let me demonstrate:
This list is easy to figure out: I want peas, carrots, and corn with my dinner.
But this one gets confusing: My sister sent me postcards from Calgary, Alberta, Toronto, Ontario, and Montreal, Quebec.
In this example, if you didn't know that the list is grouping cities and provinces together, you might think Calgary, Alberta, Toronto, and Ontario are all different cities, and you'd be confused when you got to the comma separated item after the word AND. A semi colon can clear this up, like so:
My sister sent me postcards from Calgary, Alberta; Toronto, Ontario; and Montreal, Quebec.
Just make sure that when you do use a semi colon in this way, you use it for the whole list, not just items that have commas in them.