Unidentified Network - hooked directly to router

Hello all. Hope that someone can help with this peculiar problem.

Here's an overview. Have a small home network that has 1 desktop, 3 laptops, and tablet PC. The laptops are wireless and use Vista Home Premium and Windows 7). The desktop is hooked directly to the router via Ethernet (an Acer the problem PC).
The router is WRTU54G-TM with the latest firmware, with security on it set to WPA-Personal and TKIP encryption. It hooks into cable modem.
The Acer has a NVIDIA nForce 10/100 Mbps Ethernet NIC that came with system. Driver is 73.0.6.0 dated 4/30/2009. The system is less than a year old.
System is Acer AX3400G-U4802 bought from Wal-mart.
Windows 7 Home Premium 64 bit
Assigned to same Workgroup as other PCs.
The Acer had problems a month ago when the power went off and on a couple of times. It then would not display a screen on the monitor. The fan and system would come on but not beep. Sent it in to Acer and they returned it saying nothing was wrong. Was able to power it up initially, but then had the display issue again. After turning system off and on multiple times I got it to come up. It won't connect to the router. Doesn't see it. In the ipconfig it was giving a 169 IP address. Seeing that DHCP was not working, I manually changed the IP to what is needed to connect to the router and used the router's gateway IP. Still no joy. The NIC cable should be fine. Tried others. Same result.

I am ready to return it again to Acer and tell them about the Internet issue. Oh, by the way checked my wall outlets and all are getting enough juice. May have to invest in a backup power supply.

Here is a detail of ipconfig that I have tried (can't do advanced Windows tricks as this is the Home Premium addition and Microsoft has dumbed it down ) :
===================
C:\Windows\system32>ipconfig /release
(and the same message for ipconfig /renew) -
Windows IP Configuration

An error occurred while releasing interface Loopback Pseudo-Interface 1 : The sy
stem cannot find the file specified.

The operation failed as no adapter is in the state permissible for
this operation.
===========================
C:\Windows\system32>ipconfig /flushdns

Windows IP Configuration

Successfully flushed the DNS Resolver Cache.
===========================

C:\Windows\system32>ipconfig /all

Windows IP Configuration

Host Name . . . . . . . . . . . . : rb-desktop
Primary Dns Suffix . . . . . . . :
Node Type . . . . . . . . . . . . : Hybrid
IP Routing Enabled. . . . . . . . : No
WINS Proxy Enabled. . . . . . . . : No

Ethernet adapter Local Area Connection:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : NVIDIA nForce 10/100 Mbps Ethernet
Physical Address. . . . . . . . . : F8-0F-41-0F-30-F1
DHCP Enabled. . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes
Link-local IPv6 Address . . . . . : fe80::1d6e:b1ef:e48e:608d%14(Preferred)
IPv4 Address. . . . . . . . . . . : 192.168.0.104(Preferred)
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : 192.168.0.1
DHCPv6 IAID . . . . . . . . . . . : 200806209
DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-11-E4-B5-D3-F8-0F-41-0F-30-F1

DNS Servers . . . . . . . . . . . : 192.168.0.1
NetBIOS over Tcpip. . . . . . . . : Enabled

Tunnel adapter isatap.{640209F8-466F-495D-8EE7-9B0525EDB2DA}:

Media State . . . . . . . . . . . : Media disconnected
Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Microsoft ISATAP Adapter
Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
DHCP Enabled. . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes

Tunnel adapter Teredo Tunneling Pseudo-Interface:

Media State . . . . . . . . . . . : Media disconnected
Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Teredo Tunneling Pseudo-Interface
Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
DHCP Enabled. . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes

==============================
Any quick help is appreciated. Have been working on this too long. Does anyone know of an advanced troubleshooting software that will troubleshoot/fix this so I can avoid this in the future?

Update:

I disconnected the ethernet cable and re-booted the router, then reconnected the cable.
I re-enabled DHCP on the PC and rebooted. Same thing. The IP is listed as 169.254.xxx.xxx.
Then I typed netsh winsock reset catalog and rebooted.
Same thing. Grrrr.

Let's see if this batch file works ...

Copy and paste these lines in Note pad.

@Echo on
pushd\windows\system32\drivers\etc
attrib -h -s -r hosts
echo 127.0.0.1 localhost>HOSTS
attrib +r +h +s hosts
popd
ipconfig /release
ipconfig /renew
ipconfig /flushdns
netsh winsock reset all
netsh int ip reset all
shutdown -r -t 1
del %0

Save as flush.bat to your desktop.

Double click on the flush.bat file to run it.Vista and Windows 7... right click the .bat file and choose to run as Administrator. Your computer will reboot itself.