Try a CMOS reset

I assume you checked if the new CPU is compatible with your MB

You should check with your ISP because the lease time that you mention (10 minutes) is very short. The usual lease time should be around 24h, more or less. And even when that lease time is about to expire, your computer/modem/router asks for the same IP address to be prolonged.

Also it is a good idea to check your equipment (computer/router/modem/wiring) for anything that can cause disconnections.

And more, start a CMD window and do a ping command to a server (ex.: ping 8.8.8.8 -t) to see if you have time outs in your connection (you should not).

Do you have a mouse pad? Or changed it? Or where the mouse stands (desk) is shiny?

Are You using some STP, SFTP or other cables like these? Those cables tend to have a connector with metal on it. It can be the cause of that.