I have a HP, for HP if you modify the software the 2 years guarantee is not more valid
More exactly the first thing they will do is "reset the OS to the initial condition" , (
= reformat everything ) only after they will start to look what is wrong in the hardware
With no little effort i managed to contact the technician in charge of my notebook that agree with me that the Windows partition could be restored to the "initial condition" without wipe out the linux partition...and that maybe in my cause was not even strictly needed reformat ( because the problem was very clearly a defect in the battery or in the battery charger,not in the computer itself
)
but i believe my was a very ,very rare and lucky case, and anyway bypass the bureaucracy to contact directly the technician is far to be easy
and I believe i was successful because nobody else did before does so the responsible accepted to talk mostly for curiosity , but if more people will try to the same do they will place more efficient filters to avoid theirs technicians disturbed, or loosing time conversing with the clients