"169.254" addresses are APIPA addresses (Automatic Private IP Addressing), which Windows will allocate if the network adapter is unable to connect to a DHCP server (normally your router) to get its proper address. A computer with an APIPA address cannot connect to your router or the internet so there is no question of someone hacking into your network. It will be your own PC which is initially failing to get its proper IP address. Presumably you do have your router fully operational before booting the PC? If not, then this is the cause of your problem.