Use the original bios you saved when you flashed them to the newer ones.But here is hoping you saved your bios.Generally a bad flash and the card wont even post to desktop .What your saying sounds more like a
A.Bad driver install (EVGA forums has a nice detailed guide
here B. a bad flash ,redo and test again
C. Contact Customer support threw the methods that suit you best
here ,i suggest Phone over email or tickets as its much faster to troubleshoot ,and RMA if needed .