If you're curious whether or not changing your MAC address can prevent you from being assaulted by a DDoS attack (Distributed Denial of Service attack), then the answer is yes... but it mostly works on the short-term, and it's more about getting your ISP to change your IP address if you incidentally have a dynamic IP on hand (some Internet Protocol addresses are static, which means you cannot change them; consult your Internet Service Provider for more details in regards to the state of your IP).
What does MAC addresses have to do with your IP? If you have a dynamic IP, your ISP goes about assigning you one in a random manner.
Your MAC address corresponds to this IP address, so if you change your MAC, you change your IP.
From there, you can change your MAC address one number at a time (e.g., from 12-10-B3-D5-4D-67 to 12-10-B3-D5-4D-68) or even the whole thing entirely (e.g., from 12-10-B3-D5-4D-67 to 87-16-E8-91-F2-1A). Regardless of how you change it (and as long as it accepts your changes, so it's best to play it safe and change only one number or letter of your address), it should result in your ISP assigning you a new IP address (which you can check out via sites like IPchicken.com).
The idea here is to keep your DDoS attacker guessing what your new IP address is.
If the MAC address change solution above isn't enough, then you can try to alter your MAC address of your NIC or Network Interface Card by going to your registry settings and doing it from there.
You should open Control Panel again, go to Network and Internet, Network Connections, and search for the connection that's enabled and connected.
It is important to find out where the DDoS is coming from and easily and fast block large amount of IP ranges.
Often the attackers are coming from different subnets with high amount of traffic.
By blocking off one C net at a time can decrease the load from attackers.
Once the attackers can see that you have blocked off their attacks they can try from different C classes.
Eventually you will block off all of their networks and they will find another target.
It is recommended to monitor all incoming traffic and when there is large amount of toxic traffic to block it off quickly.