Not quite certain what you're asking here.
Do you mean your 'personal' registration details i.e. Name, email address etc, etc?
or registering the software trial?
Then again, as Maya states, if you have had a previous trial version,
you cannot obtain a second trial.
Otherwise, you could download trial versions of any, repeat ANY software repeatedly,
and NEVER need to purchase it.
Traces are left in your computers registry which prevent this manoeuvre.
Feel free to clarify the position here - with additional info!!