Start by opening a cmd.exe window and running ipconfig.exe /all
Post the results.
How is the PC connected "downstairs" ? In wall cable? Wall plates? Cable running down the stairs?
Windows IP Configuration
Host Name . . . . . . . . . . . . : DESKTOP-U28A4JJ
Primary Dns Suffix . . . . . . . :
Node Type . . . . . . . . . . . . : Hybrid
IP Routing Enabled. . . . . . . . : No
WINS Proxy Enabled. . . . . . . . : No
DNS Suffix Search List. . . . . . : hsd1.in.comcast.net
Ethernet adapter Ethernet 2:
Media State . . . . . . . . . . . : Media disconnected
Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Realtek PCIe 2.5GbE Family Controller
Physical Address. . . . . . . . . : 3C-7C-3F-81-79-E8
DHCP Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
Ethernet adapter Ethernet:
Connection-specific DNS Suffix . : hsd1.in.comcast.net
Description . . . . . . . . . . . : Intel(R) I211 Gigabit Network Connection
Physical Address. . . . . . . . . : 3C-7C-3F-81-79-E7
DHCP Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
IPv6 Address. . . . . . . . . . . : 2601:243:cc80:80a0::3354(Preferred)
Lease Obtained. . . . . . . . . . : Monday, April 19, 2021 5:49:34 PM
Lease Expires . . . . . . . . . . : Monday, April 26, 2021 3:52:56 PM
IPv6 Address. . . . . . . . . . . : 2601:243:cc80:80a0:3039:ce07:61ca:d5a9(Preferred)
Temporary IPv6 Address. . . . . . : 2601:243:cc80:80a0:7d74:393a:20c4:8cdf(Preferred)
Link-local IPv6 Address . . . . . : fe80::3039:ce07:61ca:d5a9%3(Preferred)
IPv4 Address. . . . . . . . . . . : 10.0.0.74(Preferred)
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Lease Obtained. . . . . . . . . . : Monday, April 19, 2021 5:49:32 PM
Lease Expires . . . . . . . . . . : Wednesday, April 21, 2021 5:49:32 PM
Default Gateway . . . . . . . . . : fe80::226:86ff:fe54:4634%3
10.0.0.1
DHCP Server . . . . . . . . . . . : 10.0.0.1
DHCPv6 IAID . . . . . . . . . . . : 54295615
DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-28-0F-C2-1F-3C-7C-3F-81-79-E7
DNS Servers . . . . . . . . . . . : 2001:558:feed::1
2001:558:feed::2
8.8.8.8
8.8.4.4
2001:558:feed::1
2001:558:feed::2
NetBIOS over Tcpip. . . . . . . . : Enabled
My internet downstairs is my xfinity modem with my netgear adapter plugged into the ethernet port and then connected to the wall outlet. The second adapted is in the outlet upstairs by my PC setup. All the lights on the adapters show there is connection and when I plug the ethernet into my PC it shows a orange light and green blinking light.