Either your system is corrupt or your flash drive is failing. Start up from your original system installation DVD, (hold down the C key when starting. Go to the second screen pull down menu to Utilities > Disk Utility. Select your hard drive icon in the left hand column and see if you can repair it. Reinstall the system if you have to.
We have a chance to guarantee our right to repair electronic
equipment—like smartphones, computers, and even farm equipment. This is a once-in-a-generation
chance to protect local repair jobs—the corner mom-and-pop repair shops that
keep getting squeezed out by manufacturers.
Join the cause and tell your state representative to support Right to Repair. Tell them you believe repair should be fair, affordable, and accessible. Stand up for your right to repair!