classic asp checkbox uncheck and check

We want to make in classic asp a form similar like this:

<form method=post>
<input type="checkbox" name=check1 value="the first value">
<input type="checkbox" name=check1 value="the second value">
<input type="checkbox" name=check1 value="the third value">
<input type="checkbox" name=check1 value="the fourth value">
<input type="checkbox" name=check1 value="the fifth value">
<input type="checkbox" name=check1 value="the sixth value">
</form>

Select allOpen in new window

Now what we want is:

1.-Have the sixth value selected by default and the others unchecked.
2.-If the user selects any value the other values must be unchecked in other words only one value can be selected.

How can we do that if possible with code example? Because like it is the user is able to check all values at same time and we don't want that if the user checks one the other values must be unchecked. That value later we'll pass through VBscripr to same page or post form to another .asp page and the request of the values,

Thank you