Get admin rights in Windows 7 Enterprise

I have a computer ruing Windows 7 Enterprise which is locked by the system administrator.

It seems I'm not able to format an USB disk, booting an ISO file from harddisk, removing programs from the computer, etc. I'm very limited in what I can do.

Are there any ways to gain these administrator rights or clean the computer with a clean Windows or Ubuntu installation? Since I can't format an USB disk or installing a bootable Ubuntu ISO file on the USB disk, I don't know how to make a clean installation, and I'm afraid even this is also limited by the sysadmin.

The computer doesn't have a CD drive, so I can't insert a Windows CD.