Windows pre installed on partition

Hi,
Normally, for these kind of pre-installed PCs, the company will supply a few CDs/ DVDs called Recovery CDs / DVDs.

Insert the first one of them (written as bootable) into the CD /DVD drive and reboot the system. You may have to change the boot priority thro bios for this. (for this ... get into ur bios by pressing F2 / Del while booting...see for 'First Boot Device' and set it to CD/DVD)

Sometimes, the PC may allow you for some extra options for F10 / F12 keys during booting to display a menu to select boot device.

Here select the CD / DVD as boot device and run the recovery utility to restore the hidden partition and default OS.

Then play with the PC as you wish with the new OS installations

I hope this will solve your problem

bye

have a nice time