Okay, thats interesting, what version of Ubuntu are you using?
And did you use grub customizer like I said, or something else? (just curious)
When you are starting the computer, hold down the left shift button (i think) (unless you have a timer on grub).
You should now see a list that looks something like
Ubuntu, with Linux 2.6.35-27-generic
Ubuntu, with Linux 2.6.35-27-generic (recovery mode)
press E while the first one is selected and then scroll down to the line that looks like
and verify that after
ro quiet splash intel_idle.max_csate=0
(the line may be cut out/continued below, the \ will signify this)
if it is there, but wrong, correct it and press CTRL+X
if it is there, and correct, remove the intel_idle.max_cstate=0 and press CTRL+X
Report the results here.
BTW the changes are not saved this way, it is just for the current boot.