1) have you got a cross over network cable? no? go buy one, maplins and co do it ...
2) have you got a network card (not usb, not modem) looks like a phone socket just a bit wider? no? go buy a network card ...
3) download the IFA and an image (that fits to ur box i.e. 2x or 1x chip)
4) install IFA ...
5) setup ur network card, give it an IP (192.168.0.5; netmask 255.255.255.0, gatway 192.168.0.5)
6) plug in ur cross over cable into dbox and pc (do not plug the power into ur dbox)
7) start IFA set it up (i.e laod image; select network card, select yes no to null modem cable (no))
8) press start
9) read box ...
10) press ok
11) plug in dbox power.
12) .. flashing should start automaticaly .. (check the dbox LCD screen should say somethign about Flashing on it) ..
this should do it in most cases ..
read some tutorials ..