How do I remove the admin password on Ubuntu or how do I remove Linux and install Windows?

They gave the computer from the office, the computer turned out to be a surprise for me, there was Linux (UBUNTU 2.14) and even with the administrator password. We tried to get access by resetting the password through recovery mode, but nothing worked, nothing worked through grub either on computer 1 operating system Ubuntu 2.14

When logging in to gnu grub writes:

ubuntu, with linux  3.4.0-23-generic
ubuntu, with linux  3.4.0-23-generic (recovery mode)
memory test (memtest86+)
memory test (memtest86+, serial console 115200)

When you open setparams in ubuntu, with linux 3.4.0-23-generic with the E key, it writes:

recordfail
gfxmode $linux_gfx_mode
insmod gzio
insmod part_msdos
insmod ext2
set root='(hd0,msdos1) '
search --no-floppy --fs-uuid --set=root ebed8de5-5b3c-42f2-b540-c03708ddd21b
linux /boot/vmlinuz-3.5.0-23-generic root=uuid=ebed8de5-5b3c-42f2-b540-c03708ddd21b ro    quiet splash      $vt_handoff
initrd /boot/initrd.img-3.5.0-23-generic

I searched all over Google, but found nothing, Help!