As Johnwill said, the preferred method is to deal with it on the server side, not the client. If you have a machine that you always want to be a specific IP, then you need to make a
reservation on your DHCP server.
You still didn't answer my question as to why you need it to change every two days ...
It is my understanding that Windows will "cache" the IP in its registry. When it sends out a DCHP request, it will use this cached IP address from the regisry and request that it receive it. If you're relying solely on the client side, there is NOTHING on the server side that will ensure you actually get it. If the server side doesn't have a reservation, and the client releases it, DHCP is designed to be efficient and hand it out when its turn comes.
Now, as I've said, if your box is running 24x7 and it is theoretically able to reach the DHCP server 24x7, your box, the client, will request a "renewal" of the lease on the IP at the halfway point in it's lease time.
For instance ... the box I'm on at work has this when I type "ipconfig /all":
Lease Obtained. . . . . . . . . . : Thursday, March 20, 2003 4:40:27 PM
Lease Expires . . . . . . . . . . : Thursday, March 20, 2003 9:40:27 PM
Obviously, my lease lasts for 5 hours. This means at 4:40 + 2.5 hrs, it should renew itself and the "Lease Obtained" should change to 7:20 PM. However, I'm not working that late for you Doonz, so I'm not going to test it tonight.
So, your box, if its always on and your DHCP server is always available should always have the same IP. If for some reason, the DHCP server is unavailable, I believe it will request a release every 30 minutes - I could be wrong on that.
But the best thing, again, is to reserve it on the server side. However, if the server is your ISP, this is where paying them the $$$ for a reserved IP address comes in!
HTH
