pi not starting up

its a 5v power supply

i plugged the sd into the running pi and nothing happened

this makes me think it doesn't have noobs on the sd like i thought

its a 5v power supply

i plugged the sd into the running pi and nothing happened

this makes me think it doesn't have noobs on the sd like i thought

What is the  Raspberry Pi that you just got? Is it a Raspberry Pi 2?

A mistake was made: New raspberry pi's were shipped with a version of NOOBS that didn't run on the newer raspberry pi. So it is entirely possible that the preinstalled NOOBS is not able to run on your hardware. Just reimage the card with the latest version and reboot. (Then ask for your money back for the card+NOOBS... -> free card!)

Did the power supply come with it or did you buy it separately or have it laying around?

Sometimes amperage is an issue. Depending on the Pi model, it is generally recommended 1A-2A (older models need about 1A, newer models like the Pi 2 should get 2A).

It is odd that the green 'SD Drive' light does not light. If the Raspi uses a micro-SD card, make sure it is pushed in and locks into place. I know I made quite sure the first time by giving it a second push, which of course popped it back out!

I have found that my cheap USB self-powered hubs actually feed 5V back to the connected computer which will light the Raspi red power LED, but will not boot the Raspi.

Even if you have the wrong OS on the card, the green light should operate and you should get a 'rainbow square' on the screen. If the green LED operates, but there is nothing on the monitor, plug the card into a USB card interface in another computer, go to the boot partition (it's a FAT file system so any computer should do) open config.txt in a text editor and change the line,

#config_hdmi_boost=4

to

config_hdmi_boost=4

Finally, the power supply is not as important as people think. Quite a low powered device can work well.

The USB lead connecting the PSU to the microUSB power socket on the Raspi is very important. A lead much longer than one meter is almost certain to fail. Use a lead of 500 mm (half meter) or 250 mm (quarter meter) to be sure. A one meter cable should boot the Raspi up with nothing plugged into the 2 or 4 USB device ports. However, once the ports are in use, it may lead to lockups, loss of mouse and keyboard or other OS failures.

There is a short list of silly mistakes that can stop the Raspi booting. I have the complete list, if you need it. However, if you follow this check list, you might get up and running.

• Don't use the USB device ports even for keyboard and mouse until you have the noobs startup screen or the desktop displayed.
• Check that there are actually two partitions on the SD card with data in them. (you will only see the first one on a Windows computer).
• Make sure the USB power cable is no more than 1 meter in length and preferably less. If the Raspi is in a case, try it outside the case. Sometimes the case opening is too small or offset and stops the cable making a good connection.
• Make sure the SD card is fully inserted with the card contacts facing the Raspi board. Make sure a microSD card is pushed in and locked.

I have my fingers crossed for you.