In case if somebody facing this issue in the boot time , the bellow steps fixes my issue :
first of all I was getting that error Message while booting :
a tpm error (7) occurred attempting to read a pcr value
and I've fixed it by :
within your grub menu choose
Advanced options for ubuntu
from the list which will pop up choose the recovery mood :
Ubuntu, with linux x.x.x.x (recovery mood)
you will boot your system in the recovery mood, which will pop up some errors to you.
one of those errors in checking your file system :
failure file system check of the root filesystem failed
...
The root filesystem on /dev/sdaX requires a manual fsck
in my case it was /dev/sda2 ,
you need then to run the following command :
fsck /dev/sdaX
while sdaX is your boot driver.
a lot of prompts will ask you about fixing the issue,
hit yes for all those messages , after you finishing the fix , reboot your system :
$ reboot
and it should works fine.