My connection is "acquiring network address" but doesn't find it. How can I input an address that satisfies it?

If your connection is not made well enough to receive an IP address from a DHCP server, using a fixed IP address will do you no good. This is assuming that your "connection" has a DHCP server present. If you are using typical Cable/DSL router, then it will contain a DHCP server. Try using a different cable to your router and also reset (power off/on) your modem and router and then reboot your PC.

Thank you Chuck for you help. In the end it appeared that my computer was too old to support the automatic initial addressing and had to reset using the manual option.
I appreciate the trouble you went to.
Regards Thornfalcon