Call of Duty Requirements

I have an Xbox 360 4 GB. I try to install it on a regular flash drive 16 GB. I still cannot play the game even though its installed on the flash drive. Do I need an external Hard Drive or a Xbox flash drive? Are those different from regular USB flash drives? Any ideas?

You can not install an external HDD, X360 does not accept more than 32 GB external storage devices. What you can do, and I think is time for you to do it, is to get an INTERNAL X360 compatible HDD, there are 250, 320 and 500 GB X360 compatible HDDs available, you can either purchase an original X360 HDD or purchase a compatible ready to install HDD from a specialized vendor ( you can find them in e-bay ) usually those discs cost half of what a MS original disc costs.