i have problem with paypal help me!

The credit card is just for removing the limit on sending. You can't use paypal in buying over $1000 on the internet without a credit card but you can still use it to receive money. You may easily withdraw money by registering your bank account in paypal.

if you want to uplift your transaction above $500 then only you need to activate otherwise it is not needed to activate

You probably will need to put in some money into your paypal account but of course thats the problem if you do not have a credit card at the moment. If you have a friend that already has some paypal money, you can either pay the US$ equivalent to this friend to help fund your paypal account. Alternatively you can of course fund according to their other recommended and accepted modes as listed in the FAQ.