Make sure nothing is tying down your network.
1. Almost every time I play with a lagger, I tell them to make sure nothing is syncing (Dropbox, OneNote, etc.) on their computer. This usually fixes their lag.
2. Is the new computer hard wired to the router or using the wifi? If possible, try it hard wired. If you're using wifi, the computer may be too far from the router. It may help to either move the computer closer to the router or use a bigger antenna on your wireless card.
3. If the patch doesn't work, could you please post a screenshot of your port settings and post them here? Also, run a speed test at speedtest.net and a ping test at pingtest.net. Take a screenshot of these and post them as well.
I don't think you're fked. There should be a way to fix this problem.