i notice my ip change everytime i restart, can isps still track you down?
Answers:
Yes, because your ISP is who give you the IPs and they maintain track of who have which number.
Yes
Your ISP is using something call DHCP (Dynamic Host Configuration Protocol) to assign you an IP address from a pool of address that they continue.
Your computer's introduce yourself card have a exceptional identifier call a "MAC Address (MAC process Media Access Control, it have zilch to do near Apple!). This address will not conversion when you reboot your computer,and is record within your ISP's DHCP table.