About giving games away

Yea now i know it ... if the giveaway alrdy created n alrdy hv the winner ... what must i do ??

Ohh ... okay gonna tect the winner ... thx a lot for the information

You should get the winner his game. If you cant provide it you can ask the winner if it is ok to delete the giveaway and make a new one. Or make a support-ticket to request a new winner (but in this case, as it is your fault for not clarifying that some might not be able to activate it... they probably will deny it)

While typically deletions are handled exclusively between GA creator and winner, a gift having a region restriction that the GA creator was initially unaware has traditionally fallen under the special criteria from which staff will consider deletions [without winner approval] for (another notable reason is large-scale developer revocations).
Add in that the user is new, and odds aren't too disfavorable for staff approving of a deletion, especially given that staff has become even more favorable toward such matters since Steam introduced currency-based gift-locking [due to how much easier it has become for someone to encounter a region restriction without being aware of its existence before-hand].

On the other hand, staff will typically prefer not to reroll on unknown/unlisted region restrictions, due to the liklihood of getting a repeat invalid winner- so while a deletion may have a passable chance of being approved (assuming staff policies haven't shifted on the matter), a reroll is rather less likely to be.