it is most likely the 213 M iso from here you need to boot (if it is not a 64Bit processor).
http://cdimage.debian.org/cdimage/da...t/i386/iso-cd/

if you need some other processor support look here
http://cdimage.debian.org/cdimage/da...y/arch-latest/

as for "difficult installing"i think it is not too hard, my 11 year old niece managed it without problem by just reading and following instructions on screen as she went, true it was a clean hdd but if you allow Debian to auto partition it i think it will be OK (if you do not need to rescue data from it that is).
oh and i heartily agree with Harry - Verifying of md5 checksum and burning a CD at slow speed are important.