As acklan mentioned, you can use a KVM and keep the old computer as is and run it with the new one if you want. You can switch between boxes for which one you want displayed on your monitor, so you can run multiple boxes at the same time. I just used a KVM to help me with the transfer last time and now have it put away for the next time or to help others do the same. I think the data transfer cables mentioned could be the next best thing. I have purchased from Cables N' Mor in the past and they have great prices on cables, adapters and the like. They also have the KVM and should have an adapter for your cable imcompatiblilty issue. Go to:http://www.cablesnmor.com/index.asp
Also,while researching something similar, the forum recommended the following site for help. Maybe there is something there that will also help.http://www.michaelstevenstech.com/XPrepairinstall.htm
As mentioned before by fozzie & acklan, you will have to reinstall all your programs individually. It may be a good idea to go through your list and make sure you have all the media or downloaded files available. Of course, freeware you can dowload again and will be getting the latest versions that way.
One other thing, you can transfer your profiles to the new box. The profiles are the files that are stored as you customise your applications, like your browser for instance. As in the case of my email client, Thunderbird, I recently set it up on a different computer. Before I did so, I copied my profiles from the computer it had been running on the the one I was transfering it to. When I loaded Thunderbird onto the computer being transferred to, all my stored emails, my extensions, and my themes were immediately available when I opened it for the first time on the new computer. It only took a few minutes. Go to your Documents and Settings, then your User Name, then Application Data and to the program you want to move the profiles on and copy the Profile directory (folder). In my Thunderbird case, the path looked like this:
C:\Documents and Settings\(MY USER NAME)
Yours will be the same for all programs that have your personal configurations. Put the copied directory exactly in the same location on the new computer. Set up the program folder under Application Data directory and copy the Profile folder to that Program folder. If you do this before you install the program on the new compter, the apps will run just like they did on the old box. I acutally backup my Profiles from time to time, in case I have to reinstall an application I will have everthing up to date when I reinstall and open. My Firefox browser crashed recently and I was very thankful to have the Profiles available. I have spent many hours customizing Firefox with extensions and themes and I don't want to "re-invent the wheel". Transferring the profiles will really help you to have the programs on the new box run like you are accustomed to on the old one.
Additionally,the forum's "Tips and Tricks" can help you with transferring your Favorites or Bookmarks.
Good luck with it.