Try two approaches.
1. Use Network Wizard, not Simple Network Setup. Test eth0, if working click on Auto DHCP and follow the procedure; don't forget to save!
2. If this doesn't work and your router is properly configured (is it? No 10 minute time-out?), then use Static IP instead of Auto DHCP.
Nameservers should be already in, but if they are not, look them up under Menu-System-IPinfo tab DNS.
PS: For what it is worth...here is another post re an A20 Laptop.