you need to restart your PC, then it should come up with what button to press to enter the BIOS press that button (usually between F1-F12)
then find the hard drive areas and find that one then somehow reformat it, i dont know what your BIOS is like, and ive only looked through mine a couple of times
My Bios screen looks very diffrent, to anything i have seen before, looks futureistic but i inserted the Windows CD, restarted the computer, went into Bios.
exited bios,
then boot from CD came up.
Then i clicked advanced, then advanced agian, clicked Delete on both options
then clicked my main one with the highest memory,
you dont need that AV trial shouldnt of even added it, it will just clog up your hard drive even if you uninstall it, especially as you would have just got a free AV anyway, also cant recommend enough Malwarebytes Anti Malware alongside AVG