Strange behavior. I have a similar problem and i'll tell you how i fix it but i dont know why it happens.
I have a Linksys router WRT54G, if that makes any difference.
Suddenly, once in a while, her ip address connection to the internet gets changed. normally it is a subnet address like 192.168.1.201. That number is assigned by DHCP on the router.
Just today it happened and i found that her connection is now 169.254.159.128, just like you! When this happens her laptop can not connect to the internet.
Doing a lookup on that IP address gets the following:
OrgName: Internet Assigned Numbers Authority
Address: 4676 Admiralty Way, Suite 330
City: Marina del Rey
NetRange: 169.254.0.0 - 169.254.255.255
NetType: IANA Special Use
Comment: Please see RFC 3330 for additional information.
A Google search on "BLACKHOLE-1.IANA.ORG" finds "http://www.iana.org/abuse/faq.html"
which has the following:
"Autoconfiguration" IP Addresses:
169.254.0.0 - 169.254.255.255
Addresses in the range 169.254.0.0 to 169.254.255.255 are used automatically by some PCs and Macs when they are configured to use IP, do not have a static IP Address assigned, and are unable to obtain an IP address using DHCP.
This traffic is intended to be confined to the local network, so the administrator of the local network should look for misconfigured hosts. Some ISPs inadvertently also permit this traffic, so you may also want to contact your ISP. This is documented in RFC 3330.
A Google search on "Autoconfiguration" IP Addresses finds "http://support.microsoft.com/kb/220874"
which has the following:
Click Start, click Run, type "cmd" (without the quotation marks), and then click OK to open a MS-DOS command line window. Type "ipconfig /all" (without the quotation marks), and then hit the ENTER key. If the 'Autoconfiguration Enabled' line says "Yes", and the 'Autoconfiguration IP Address' is 169.254.x.y (where x.y is the client's unique identifier), then the computer is using APIPA. If the 'Autoconfiguration Enabled' line says "No", then the computer is not currently using APIPA.
My interpretation: For some reason the DHCP service is failing on the router so the PC resets to an Autoconfiguration" IP Address.
This is what I do to reconnect to my local network.
1. run the 'cmd' window as above. Run the command "ipconfig /release".
2. Now run the command "ipconfig /renew"
Now if you then run "ipconfig /all", you should see that your IP Address is now safely in a local IP range, like "192.168.1.X".
You should not have to reboot.