I want to reformat my pc but it seems my own computer does not want me to.
It always gives out a stop error message saying something like this:

>>Your windows had been shut down to avoid damage.
1.Please scan your PC for viruses.
2.Scan hard drives so it be powered or terminated correctly.
3.Run CHKDSK/ F for errors.

Well I have done 1 and 3 still the stop error above always occur.
How to do number 2?
What does F mean in CHKDSK/ F? Is is F:\?
Well if it is I dont have a drive F:\.

Well actually I had one but the it is because of powerISO.
I installed it and suddenly F:\ appeared.

Is the powerISO responsible or other error that exists?

What should I do? Step by step please. Thank You