Firstly, sorry for bumping up such an old topic, but seeing as it was on the first page of google search for "Maxtor 3100 not recognised" i figured it gets visited a fair bit by people with this same problem
My sister has a 3100 and it started playing up the other day and refused to work 3 minutes after turning on her computer (i'm not sure that this is associated or not but i wouldn't bet against it). That is it was accessible for 3 minutes after restarting that is, then it went to the old "delayed write failed" routine....
Basically in an attempt to save her stuff she brought it to me and i plugged it into my Laptop (a Dell D610) and I was having the same problem as you have all been having. To get it to work however, I tried all the stuff that has been suggested so far, and finally just tried switching the usb cords around with my usb hard drive. It worked fine, intsalled properly and I am backing up all of my sisters info as I type,
So, my suggestion:
1. Don't buy one of these Pieces of crap
2. if it is too late to carry out #1 Plug Hard drive into wall, and get a different usb cable.
3. It may be an idea to plug the usb into a motherboard port as well as they will probably be better supplied with power than a PCI card if you are using one of them...
well... it worked for me
EDIT: The usb cable from my sisters hard drive works fine with mine so it is not as if the cable was damaged