windows 8 - How to validate recovery partition for modifications?

I bought second-hand notebook (sony vaio ultrabook duo) with Win8 . I'd like to have clean system unaffected by malware. Which gives me two possibilities.

a) Reinstall from new source - This way I will, however, lose warranty and OEM Windows key.

b) Reinstall from recovery partition - Where is a risk of having it modified by malware.

Is there any way how to validate recovery partition for modifications?

Recovery partitions (visible to Windows) are often compressed and split into smaller files. The compression and splitting would make it almost impossible for malware to crack open the file and infect the restore data.

Restore partitions NOT visible to Windows are usually in a format not visible to Windows - i.e. ext or other formats that Windows doesn't know how to use.

Windows 8 recovery (just like Win 7) is almost 100% done using a WIM file with a custom WinPE to begin the restore process and automate everything. Before you do the restore process, as I've mentioned in other posts, make sure you've exhausted all avenues to build your own recovery disks - or even buy the manufacturer disks. Then you will be guaranteed to have working disks. You can buy manufacturer disks at any time - they'll be happy to take your money for the price of a few DVDs. I would recommend you make your own, however! The disk writing application will write and verify the disks so a portion of the "split" WIM file will be verified anyway.

On a side note: If you have bought a second hand laptop then, most probably, you don't have a warranty anymore anyway... the warranty is usually only valid to the original purchaser, unless you have gone through a warranty transfer process??