Nexus 5 won't finish booting and cannot recover

I have a Nexus 5 that cannot finish booting and boot loops. I can get to recovery but it cannot clear the cache and cannot recover either. It just reports that it fails doing anything. I did clean the on off button and have messed with it endlessly but it makes no difference. It does not seem to me that the on/off button is the problem.
When it boot loops, I can hold down the power button continuously and the phone will shut off after two boot loops. otherwise it will keep trying until the battery goes dead. The phone does still take a charge.
I have hooked it up to my desktop and tried to mount the system in the bootloader but it reports that it fails to do that also.
My main concern at this point is to be able to get my pictures off the phone but perhaps they are gone forever.
Any ideas would be most helpful. I have another phone to use so I am not stranded but would sure like to get my pictures back if possible.
Thanks for any assistance.