You can download the diagnostics software for it from the xrite website as well as the most current drivers for it.
http://www.xrite.com/product_overview.aspx?Action=support&ID=1014
And AF is correct it that it can be finicky about the USB port it is on. The lamp in them draws a good bit of power and it works best if it is not on a shared port. By shared I mean your PC probably has 2 or 3 USB controllers, each of which is tied to one or two of the USB ports on the computer (front or rear). The computer will not indicate which ports are shared with another on a controller. It is best though to use a rear USB port - if you want to get adventurous you can look in Windows Device Manager to see what is on a controller with another device. Each controller will have a Hub which will be for two or more physical USB ports. Look under Universal Serial Bus Controllers then double click each Root Hub, then click the Power tab. From there you can see what is connected to a particular controllers hub. It will take trial and error to move USB connections around to isolate it. Attached shows mine on a controller hub by itself. On my workstation - it does not work properly on one of the front ports (even though it is still not on a shared hub), I think because the front ports are not capable of providing as much power as the ports directly on the motherboard.
If you got the fold up base for reading color charts in that also help some to keep it in line just right when scanning the strips in but is not required. Also they usually come with a weight thingy to hang it on your monitor for profiling your monitor. Does make it easier for full monitor profiling but not mandatory. You can just hold it against the screen where you need to. Another thing most are not aware of - you can also use it in the designer part of Flexi to scan a custom color in. Under the View menu choose Color>Color Specs - on that screen there is a measure button.... Choose New first so you do not overwrite one of Flexi's built in colors - give it a name and choose the mode (I prefer Lab since that is the most accurate). Also - make sure you have your i1 selected and calibrated under Edit>Preferences>Tools first though... Its not an exacting thing though. I've seen where others expect it to be dead on with a Pantone color value for example. You can make a square or whatever and assign it a Pantone Spot color then look at that spot colors Lab values. Then take an actual Pantone book and measure that exact same color with the device and it is NOT going to give you the exact same value. It will be close but not exact. For example in this test I just scanned 186C from the Pantone book and put it next to a shape filled with the Pantone built in 186C spot color. It is very close. The built in spot color Lab values are 45, 68, 40 - the scanned lab values from the Pantone book for the same color scanned as 44, 67, 43. Close enough for me. The one on the left (selected) is what I just scanned in from the Pantone book, the one on the right is the pre-defined Pantone spot color.
I know a LOT of people on this site simply hate FlexiSign. That being said - I think the majority of those have never really dug into it's depths and got it configured just right. Flexi uses the APPE as it's RIP engine (they actually license the Adobe PDF Print Engine) so its no real surprise that Flexi really prints best with RGB files, specifically RGB files with the Adobe RGB profile assigned to them. Most RIPs charge you extra for every little thing. Flexi has full support for an i1 and profiling built in, color measuring is built in, supporting multiple printers and cutters is built in, etc.