I have 8 Raspberry Pi Computers in my class. After flashing the most recent version of Raspbian onto 8GB SD cards which were originally sold with NOOBS on them (the cards are therefore Raspberry Pi ready), we were able to login to the desktop and connect to WiFi through the school WiFi network. We are able to browse on the web and also ping a range of websites through the terminal.
On 7 of the machines when we ran
sudo apt-get update
Hit http://raspberrypi.collabora.com wheezy Release.gpg Hit http://raspberrypi.collabora.com wheezy Release Hit http://mirrordirector.raspbian.org wheezy Release.gpg Hit http://archive.raspberrypi.org wheezy Release.gpg Hit http://mirrordirector.raspbian.org wheezy Release Hit http://archive.raspberrypi.org wheezy Release Get:1 http://raspberrypi.collabora.com wheezy/rpi armhf Packages Get:2 http://mirrordirector.raspbian.org wheezy/main armhf Packages Get:3 http://raspberrypi.collabora.com wheezy/rpi Translation-en_GB Get:4 http://raspberrypi.collabora.com wheezy/rpi Translation-en Hit http://repository.wolfram.com stable Release.gpg Hit http://mirrordirector.raspbian.org wheezy/contrib armhf Packages Hit http://mirrordirector.raspbian.org wheezy/non-free armhf Packages Hit http://mirrordirector.raspbian.org wheezy/rpi armhf Packages Get:5 http://archive.raspberrypi.org wheezy/main armhf Packages Get:6 http://mirrordirector.raspbian.org wheezy/contrib Translation-en_GB Get:7 http://archive.raspberrypi.org wheezy/main Translation-en_GB Get:8 http://mirrordirector.raspbian.org wheezy/contrib Translation-en Get:9 http://archive.raspberrypi.org wheezy/main Translation-en Get:10 http://mirrordirector.raspbian.org wheezy/main Translation-en_GB Get:11 http://mirrordirector.raspbian.org wheezy/main Translation-en Get:12 http://mirrordirector.raspbian.org wheezy/non-free Translation-en_GB Hit http://repository.wolfram.com stable Release Get:13 http://mirrordirector.raspbian.org wheezy/non-free Translation-en Get:14 http://mirrordirector.raspbian.org wheezy/rpi Translation-en_GB Get:15 http://mirrordirector.raspbian.org wheezy/rpi Translation-en Hit http://repository.wolfram.com stable/non-free armhf Packages Get:16 http://repository.wolfram.com stable/non-free Translation-en_GB Get:17 http://repository.wolfram.com stable/non-free Translation-en Fetched 65.2 kB in 13s (4,992 B/s) W: Failed to fetch gzip:/var/lib/apt/lists/partial/raspberrypi.collabora.com_dists_wheezy_rpi_binary-armhf_Packages Hash Sum mismatch W: Failed to fetch gzip:/var/lib/apt/lists/partial/mirrordirector.raspbian.org_raspbian_dists_wheezy_main_binary-armhf_Packages Hash Sum mismatch W: Failed to fetch gzip:/var/lib/apt/lists/partial/archive.raspberrypi.org_debian_dists_wheezy_main_binary-armhf_Packages Hash Sum mismatch E: Some index files failed to download. They have been ignored, or old ones used instead.
We can ping archive.raspberrypi.org etc without any problems.
On one of the machines
sudo apt-get update worked and the pupil was able to install scrot but then we removed scrot and then attempted a reinstall of scrot we received the exact same errors as above.
I have attempted all the suggestions from a similar error I had before posted here on stack exchange including reflashing the SD card again.
Assistance very much appreciated.