Network problem with Windows 7 after sleep and after reboot of PC

[#1]

I have been seeing problems with the Windows 7 64 bit computer not finding the LAN network when waking from sleep. It does eventually after about a minute. I have the LAN connection on the motherboard set to stay powered up
I just had a play using ipconfig /all and these are the results
No LAN detected

Windows IP Configuration
   Host Name . . . . . . . . . . . . : Jim
   Primary Dns Suffix  . . . . . . . :
   Node Type . . . . . . . . . . . . : Hybrid
   IP Routing Enabled. . . . . . . . : No
   WINS Proxy Enabled. . . . . . . . : No
Ethernet adapter Local Area Connection:
   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Realtek PCIe GBE Family Controller
   Physical Address. . . . . . . . . : 00-1A-4D-59-68-29
   DHCP Enabled. . . . . . . . . . . : Yes
   Autoconfiguration Enabled . . . . : Yes
   Link-local IPv6 Address . . . . . : fe80::3075:bb5f:9d3d:1bc4%10(Preferred)
   Autoconfiguration IPv4 Address. . : 169.254.27.196(Tentative)
   Subnet Mask . . . . . . . . . . . : 255.255.0.0
   Default Gateway . . . . . . . . . :
   DNS Servers . . . . . . . . . . . : 8.8.8.8
                                       212.159.13.50
   NetBIOS over Tcpip. . . . . . . . : Enabled

LAN Detected

Windows IP Configuration
   Host Name . . . . . . . . . . . . : Jim
   Primary Dns Suffix  . . . . . . . :
   Node Type . . . . . . . . . . . . : Hybrid
   IP Routing Enabled. . . . . . . . : No
   WINS Proxy Enabled. . . . . . . . : No
Ethernet adapter Local Area Connection:
   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Realtek PCIe GBE Family Controller
   Physical Address. . . . . . . . . : 00-1A-4D-59-68-29
   DHCP Enabled. . . . . . . . . . . : Yes
   Autoconfiguration Enabled . . . . : Yes
   Link-local IPv6 Address . . . . . : fe80::3075:bb5f:9d3d:1bc4%10(Preferred)
   IPv4 Address. . . . . . . . . . . : 192.168.0.3(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.255.0
   Lease Obtained. . . . . . . . . . : 28 December 2011 11:01:51
   Lease Expires . . . . . . . . . . : 30 December 2011 10:23:51
   Default Gateway . . . . . . . . . : 192.168.0.1
   DHCP Server . . . . . . . . . . . : 192.168.0.1
   DHCPv6 IAID . . . . . . . . . . . : 234887757
   DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-12-72-15-1D-00-1A-4D-59-68-29
   DNS Servers . . . . . . . . . . . : 8.8.8.8
                                       212.159.13.50
   NetBIOS over Tcpip. . . . . . . . : Enabled

The problem appears to be that the adapter is losing the Gateway and the IP4 Address but not the IP6 address
Title changed as I get the same delay when the computer is rebooted - does this point towards a router problem

[#2]

To add - and I don't know if it is relevant
I am getting intermittent DNS lookup failures on all the connected devices - one Windows 7 and one XP both wired also a laptop XP wireless but with no indication of any problems with the router or the connection
I tried switching the DNS servers around in the router but it didn't help
Ignore this - I found this in the router log at about the time we had the problem

Tue, 2011-12-27 19:32:23 - LCP down.
Tue, 2011-12-27 19:32:25 - Initialize LCP.
Tue, 2011-12-27 19:32:25 - LCP is allowed to come up.
Tue, 2011-12-27 19:32:26 - CHAP authentication success
Tue, 2011-12-27 19:39:24 - Administrator login successful - IP:192.168.0.3
Tue, 2011-12-27 19:39:32 - LCP down.
Tue, 2011-12-27 19:39:33 - Initialize LCP.
Tue, 2011-12-27 19:39:33 - LCP is allowed to come up.
Tue, 2011-12-27 19:39:39 - LCP down.
Tue, 2011-12-27 19:39:47 - Initialize LCP.
Tue, 2011-12-27 19:39:47 - LCP is allowed to come up.
Tue, 2011-12-27 19:39:49 - CHAP authentication success