Doing an image will be a huge cluster----. Windows wont run because it was activated on the old platform and when it sees the new hardware it'll stop and make you call microsoft and explain to them why the old license has been moved to the new platform, and what you're doing with the old platform. After a while you'll probably be allowed to change the windows key on the new machine but only if it has one. You said there wasnt any windows product loaded on it before, so I presume theres no key.
Next, all the drivers will be wrong and you'll have to remove all the old devices and have windows look for new ones, supply driver disks or downloads for all the stuff in the 'new' box.
Next, you'll have to reinstall all of your applications. There arent many products that can lift apps and settings from one machine and carry them over to another intact.
Next you'll have to root out all your files and settings and copy those over. Windows Files and Settings Wizard can do a lot of that but I wouldnt bet on it getting everything.
Solution:
Wipe the "new" machine. Obtain a new windows key for it. Install windows. When it quacks for a driver for something, go make a cd on your other machine and insert it. When thats done, install all your applications. When thats done, use windows file and transfer wizard to copy your settings and files to an external hard drive or burned dvds and use the files and settings wizard on the "new" machine to put them back. If you've got gigabytes of files and settings you do NOT want to use a cat5 network connection to transfer them, it'll take hours and hours and hours.
Then keep the old machine or put the old machines hard drive into an HD enclosure and retain it for the time six months from now when you go looking for a file and discover that the wizard didnt copy that directory or files.
On the new machine, unless its a 3GHz quad core extreme edition machine with 8GB of ram, a terrabyte of raid 5 disk and has latest generation dual SLI video cards, it wasnt worth 3000.
At this point you can buy a desktop from the dell outlet for under $400 thats probably more computer than 98% of people really need, it'll already come with windows installed, and it'll have a fresh warranty.