creo que esto te servira
Código PHP:
<form name="MyForm">
<input type="checkbox" name="Rec" value="1" onClick="if (this.checked) { document.MyForm.Olv.checked = 0; document.MyForm.Olv.disabled = 1; } else { document.MyForm.Olv.disabled = 0; }">
<input type="checkbox" name="Olv" value="1" onClick="if (this.checked) { document.MyForm.Rec.checked = 0; document.MyForm.Rec.disabled = 1; } else { document.MyForm.Rec.disabled = 0; }">
</form>
<input type="checkbox" name="Rec1" value="1" onClick="if (this.checked) { document.all.Olv1.checked = 0; document.all.Olv1.disabled = 1; } else { document.all.Olv1.disabled = 0; }">
<input type="checkbox" name="Olv1" value="1" onClick="if (this.checked) { document.all.Rec1.checked = 0; document.all.Rec1.disabled = 1; } else { document.all.Rec1.disabled = 0; }">