I think I have downloaded all the drivers, so I'm not sure what's going on. I went to Tools and "Port" is grayed out. I've also tried connecting to all my USB ports and keep getting the same error message.
My computer is a Toshiba running Windows 8.1 x64 if that helps at all.
This is the first time I'm working with an arduino, so it's ok if you explain things to me like I'm a small child haha.
You need to see something in windows DEVICE MANAGER.
If you cannot see the device list in some form there then the IDE will not see it either.
The walk through for to the lily is HERE.
Its easy enough to follow but if you are still stuck come back with any updates.
Did you do the walk through ?
I don't have a lilly but those walk throughs tend to be pretty accurate and reliable.
Also under windows (most flavours) its often best to install such as the IDE as "ADMINISTRATOR" and this is ABOVE a user with just admin rights.
Same goes for drivers on occasion.
Other good things to know at this end are security being used as some AV tends to be over aggressive and some phone apps for syncing phones can also cause issues.
What are you using for the upload device itself ? (Links and pics always welcome)
Make sure initially that you have nothing connected to the board JIC its something connected in a way that may interfere with uploads.
Which IDE ? (version)
Also ensure your boards versions are updated under board manager in the IDE
Good chance the drivers you should be using are in a folder in the IDE install directory called "drivers"
You may want to delete those from device manager including the drivers if it asks before going any further.
C:\Program Files (x86)\Arduino\drivers
If you are running x 64 then fire up "dpinst-amd64" ignore that it says AMD if you are on an INTEL cpu as it covers both.
If you are running less than x64 fire up "dpinst-x86"
Do so as ADMINISTRATOR and ensure you either turn off driver signing or tell it to ignore driver signing.
Search google for that one under win 8 "run as administrator"
Not being funny or anything but its a learning curve that will get you up to speed a little on how to search for things and get the best answers quickly.
That first link has some good info but some of it is misleading.
He refers to white and black cables not working which is utter rubbish.
The real consideration and the only one that should be of concern is "Can it sync data from your phone" ?
Does the computer make a "hardware found noise" when plugged into an Arduino ?
Stick to shorter cables (not always true but a safer bet).
Don't use USB 3.0 ports or cables (again not always true but again often a safer bet to stick to USB 2.0 ports.
If you only have USB 3.0 ports then very often a POWERED USB 2.0 HUB of reasonable quality will work between the Arduino and the computer as a buffer.