the dhcp address does not affect the ability of the router to route traffic form your network--assuming the range is within the network
If you have a standard router, and given your numbers, your NETWORK ranges from 192.168.1.1 all the way to 192.168.1.254 (this is because the subnet mask determines the network (assuming you have a traditional subnet mask of 255.255.255.0.
Your DHCP server is simply in charge of handing out ip addresses within the range you specified....it does not know how large your network is.
This is not always obvious when you get these consumer grade devices that do everything for you. In my case, for example, I have a small network with a router/gateway, I have a dhcp server, a domain server, webserver and a file server and four workstations. Domain, dhcp, file and webserver all are statically assigned. The DHCP server then hands out ip leases beyond the range of the static ips on the network (10.0.0.1 through 10.0.0.10. I could add 16,000+ machines to a network set up this way and they would never interfere....well, too much info...
I do not know for certain what is going on at the moment, but let's rule out the obvious chance of ip conflicts as your wife's computer enters and leaves the network.
you can download the malicious tool and run it without installing it from here (it is a stand alone file)http://www.microsoft.....bRemoval+Tool
Or, get Stinger from herehttp://vil.nai.com/vil/stinger/
Same thing...no install