Right, what you might consider is the following:

Let's say that you've got a row and in this row the possibilities for each of the nine cells are as follows:

{1,2} {

3} {7,8,9} {1,2} {1,4,7} {

5} {

6} {2,7} {4,7,8,9} (By the way, the

bold ones are just cells in which you already know the number.)

Now, notice that cells 1 and 4 only have the options {1,2} in them. This means that if these

two cells can only contain these

two numbers, then these two numbers

must be in these two cells. Which therefore means that these two numbers

can't be anywhere else. So, look at cell 8. This could only be 2 or 7, but we've just worked out that, in fact, 2 can't be there! So, it must be a 7. If you follow that, you can do the same to cell 5. This cell looks like it could be {1,4,7}

but we've just proved it can't actually be a 1, and after the last step, we now know it can't be a 7 either - so it must be a 4. And so on...

This method is known as

naked pairs (I think!) and if you follow what I've just said, you can probably see how it would also work with

three numbers and

three cells, and still higher numbers.

As Paul said, it is fun to work out the higher strategies for yourself, but if you like you could do a lot worse than read the following two sites for some explanations:

http://www.angusj.com/sudoku/hints.phpand

http://www.simes.clara.co.uk/programs/sudoku.htmBy the way, as to posting the grids, I'm sorry to say I don't know - I just type in things like:

2 * * 4 * 1 * * 7

for each line, and so on.