invalid device signature on attiny85

I've no idea why I get this error:

avrdude: Yikes!  Invalid device signature.
         Double check connections and try again, or use -F to override
         this check.

I've checked all the connections using a continuity test, so I am a bit confused. I have ISP sketch uploaded to board correct bored selected (attiny85) and arduino set as ISP. anyone know what else might cause this? It was working perfectly yesterday...

wasn't either of these as well: http://arduino.cc/en/Guide/troubleshooting

If you turn on verbose upload logging you will get to see the the signature that is read and the signature that is expected.

If the signature being read is 0x000000 or 0xFFFFFF then something isn't working in the SPI interface. Perhaps the chip fuses have been set to disable reset, disable serial programing, or require an external crystal for the system clock.

reseting the fuses seemed to have worked. thanks!