How can I reset order number?

Hi.
I want to re-start order number from 1 without loosing current user infos. How can I do that?

I don't believe that order numbers can "start over". You can use your admin's Tools->Store Manager to reset the order number to a value larger than the current, but I don't think that you can reset the order number to 1 without losing data and/or corrupting your database.

Can't do that as currently customers have orders in that range

You can begin it at wsome number higher than where you are
admin > tools > store manager > Reset Current Order ID

I only need customers registration info.
I don't need customers order info. Can I delete all order infos from database? If yes, is there any easy way. I don't want delete all orders manually. May I reset order number from 1 that way?

Yur customers will not be able to see their past order history if you do

Why is setting to "1" important?
Why wouldn't "100,000" be sufficient?

Thank you guys. Zen card rocks.