How Can I change the fields order without using CCK I want to change the order of the fields in each node. I know that I can use CCK but I would like to do this in hook_node_load

Is it possible?

Thx :)
In my views cck will always overwrite the weight you assign programmatically, best way should be arranging the cck fields in order you want.
If you want to change order on the fly using javascript can be an option too,but not sure if it is good option
for example

jQuery('.field-name-field-test-taxonomy').insertAfter('.field-name-field-simple-text-field');


where ".field-name-field-test-taxonomy" and ".field-name-field-simple-text-field" are the wrapper div for cck fields respectively.with out the above js code the default taxonomy field was coming before the simple-text field but with we simply change the order.
hope it helps.