[HELP!] Failed CM flash & now wont mount /system

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http://forum.xda-developers.com – I am using TWRP, I factory reset fine. I then lined up 3 zip files to flash. CM10.1, Gapps and Cerberus The screen turned off while flashing and I panicked. It wouldnt turn on again. I'm thinking it was because of the screen off delay. I panicked and pushed all of the buttons several times but couldn't get the screen to turn on again. Now I've turned off the screen off delay and now I'm trying to re install CM but it keeps getting the following E: Unable to mount ' /system ' I can still access TWRP recovery and Download. Is there any way to restore the partitions? (HowTos)