Debugger called: , panic(cpu 8 caller 8xffffff80167ce524)

Hi,

I cannot start my MacBook Pro anymore. I bought it in 2010, it's a 13" originally in snow Leopard I think. Since then I updated the OS to Mavericks a little over 1 year ago (which turned to be a very bad idea... My macbook has been increasingly slow ever since. But whatever).

When I try to start it, it keeps displaying this :

Then restarts and tells me to hit a key to restart or wait for the restart... then this again. Then again and again

I don't know what to do. I can't access anything.

I tried - to hold the maj key while starting it but it did not work.

- to hold the command + v keys (to access the verbatim... Don't know what it does ** saw it was a probable solution) but it did not work neither

What should I try ?