Windows 7 - re install clean windows 7

hi guys this is my first post ...
i have a comp with a single hdd which has 4 drives.. i had xp on c drive and and windows 7 on i drive.. and wen i checked it turns out c drive is the system drive.. so every time i log on windows 7 dose n't show as c drive.. so basically i wanna remove it and start afresh with a 64 bit version (ya before i had a 32 bit version).. and so basically wat i want is when i install the 64 bit version it should be c drive.. and wen i install xp that drive should show c drive..
as in each operating system should show as c drive in the respective drive it is installed in.. and i dont wanna touch the other two drives cause i have a lot of data on them..
i hope i've explained clearly enouhg..

Have read of those tutorial:
Dual Boot Installation with Windows 7 and XP
SATA Drivers - Load in Windows XP Setup on Dual Boot
SATA Drivers - Slipstream into Windows XP CD
Use EasyBCD 2.0 in Win 7
Download EasyBCD 2.1 - NeoSmart Technologies

A bit more reading.
BCDEDIT - How to Use
System Restore Points - Stop XP Dual Boot Delete - Vista Forums

i dont wanna dual boot.. in case i havent mentioned i have removed windows xp but c drive is still the system drive.. basically i wanna remove delete the two drives c drive on which xp WAS installed.. and i dive on which 7 IS installed.. and start fresh wit a windows 7 making that drive the system drive.. i guess i can simply install 7 in the c drive but i dont wanna risk any fuure problem.. so how do i delete it?? i tried doing it with a windows 7 installation cd.. it formated but its still the system drive.. how do i make it such tat my hdd dosnt have a system drive to install a fresh copy of 7..??

Back up your DATA first.
Restore Backup User and System Files
Windows Easy Transfer - Transfer To & From Computers

Than
SSD / HDD : Optimize for Windows Reinstallation
Clean Install Windows 7

Windows 7 doesn't show as C because you installed it from XP which held onto the letter during install.

Always boot the installer. Select Custom Install, then Choose carefully the XP and Windows 7 partition, click on Drive Options to delete both, then recreate and format install partition as desired. Clean Install Windows 7

If you don't touch any other partition your data will be safe. But you should back it up anyway.

It would be best if you post back a screenshot of your maximized Disk Mgmt drive map with listings, using Snipping Tool in Start Menu. There may be unseen issues that need to be taken into account.

i've attached two screen shots as asked.. hopefully its self explainatory.. and just FYI.. c drive has ubuntu installed through windows 7 using wubi.. in case that makes any diffference..
and the vinay ns and d link server are external hdds..

Move any data off Windows 7 partition into your other data partitions, shrinking Windows 7 if necessary as you go to make more space for the data partitions, which can be resized easily in any direction using free Partition Wizard bootable CD which will not fail. Easeus can and will fail.

Use free Partition Wizard bootable CD to delete Windows 7 partition, then create a new Logical Data sub-partition there, or shrink the Logical Extended partition from the left to make more space for C.

If you have GRUB on C, rightclick it with PW to Wipe it with at least one set of zeroes to erase all GRUB.

Boot the Windows 7 DVD, select Custom Install, use Drive Options to delete C, create a new partition there, format and install Windows 7. Follow the tips given here (which apply) to get a perfect reinstall: Reinstalling Windows 7

As long as you don't touch the other partitions your data will be safe, however you should back it up when doing any resizing or install anyway.

sry for the trouble but this seems a llil bit confusing..
i dont need any data on I drive and C drive.. i wnana wipe them both clean.. i heard this trouble is because C drive is the system drive, so i wiped XP and deleted it and created another parttion.. and as expected i had problem booting into 7.. and i ended up trying the recovery disk adn stuff.. somehow i ended up booting into 7 doin something.. but turns out c drive is still the system drive.. so i wanna wipe both theses drives clean.. so i end up with no system drive.. and thus i can do a clean install of Windows 8 leaked version or windows 7..
and fro wat i understood from ur above post i just need to delete the two drives from a windwos bootable installatin disk and i should be good to go right??

OS's can not boot from Logicl drive, which your Windows 7 drive is. There System will be C:
Your biggest problem is is playing with 3rd party partitioning tools & Linux.

You can delete C with the booted Windows 7 Installation DVD, then create a new partition, format and install to C.

I would not want to take a chance using the installer to delete only the I Logical subpartition as it could delete the whole extended Logical partition. This is why I would use PW CD which is known not to fail in operations such as these.

And if GRUB was on C then I would want to wipe it first, not just delete, as GRUB can corrupt Windows 7 until wiped from the partition on which it was installed.