Formated primary,now want assign path in win

My hard drive was split up into two parts, one part was (C:) and the other (E:). This was set as a standard and came when I brought the computer,which is an li 27 27 laptop.

I had alot of viruses on my computer so I decided to format my whole drive and start fresh,when loading windows 7 os disk,I get up to the part were I'm asked to choose which hard drive I want to insall (win 7).I pick the one that It was on before (C:) and am told windows can not instal to this path because the hard drives not In Ntfs formate.So fo the sake of me using the net for trying to figure out a solution to this problem I install to drive (E:).Once my computers up and running I go my computer and drive (E:) has now become drive (C:) and other drive is none existent in windows.I do some research and through this I go into disk managment and try to assign a Drive path letter manualy.I find the drive in disk managemt but the trouble is I can not assess the prive letter path option to do so.Deleat and Help are only my options.

Now I'm stuck and losing out of 63 gb of hard drive capacity,which bits the biscut!

Can anyone suggest anything?