Have my parents old computer. What do I do with it?

[HeK]

Depending on the type of wireless router that you currently have, you may be able to disable the DHCP server and use it as a switch/AP.

Also depending on the type of router, you may be able to install a custom firmware which would make it into a much better switch/AP.

[Kirby]

Depending on the type of wireless router that you currently have, you may be able to disable the DHCP server and use it as a switch/AP.

This.

Before I upgraded everything in my network to gigE, I used my old router with DHCP turned off as the switch behind my gateway PC. Now I've got a dedicated Smart gigE switch behind it, but the router worked very nice.

[Cloud_9ine]

So theoretically I could just turn off the DHCP Server, change its connection to just a static IP, disable NAT (, Possibly fiddle with settings a bit more) and use that as my switch/AP for now and let the Gateway take care of aspects such as DHCP, firewall, etc.?

[HeK]

So theoretically I could just turn off the DHCP Server, change its connection to just a static IP, disable NAT (, Possibly fiddle with settings a bit more) and use that as my switch/AP for now and let the Gateway take care of aspects such as DHCP, firewall, etc.?

Pretty much. You shouldn't have to disable nat (if that is even an option on your device) as it will no longer be specified as the gateway device for your subnet.