first of all, linux cant write NTFS (thsi is not technically 100% true but its VERY BAD to try it), and fedora doesnt even ship with an ntfs driver.
For this reason, if theres nothing on that 100gb partition i woudl change it to fat32. And while u shouldnt really have fat32 partitions bigger than 20gb (some ppl say 40) as long as you only put big files (>1mb) on it u shouldnt have a problem. - ive got a 140gb fat32 partition full of ISO's, music and movies here without any issues.
so those 2 5gb partitions will need to be reformatted during your install, mandrake probably did this kinda automatically and fedora shoudl ask u to reformat it when u tell it u want to isntall there, (select ext3 for compatibility reasons). This may fix that "need root.." error if it was "this partition is nto useable as root" although i have heard of the fedora isntall program giving errors liek that for other reasons which i dotn remember how to fix.
Int the mandrake isntll (at least in my 9.0 installer) there was an option to "load GUI at boot" or something, if u said no here, or if your graphics driver isnt happy, it will load a terminal. type mcc and go to display option, i seem to remember there being an option here for "load xfree on boot" turn this on. (u can also edit the /etc/inittab file but this is harder)
now type
Code:
su
<enter your root password here>
service dm start
this will start your GUI provided your graphics card is happy.
if this fails post up whatever error it gives you.