Corrupted OEM Partition - best method to reinstall Windows 7?

I have a Lenovo OEM installed copy of Windows 7. I need to reinstall Windows 7 on it using my own disk.

On the laptop, I have 4 partitions;
Partition one called SYSTEM_DRV (200MB),
Partition two called Windows (890 GB),
Partition three for Drivers (25GB)
Partition four (20GB).

If I need to reinstall a clean Windows 7, what do I do with these 4 partitions?
Can someone please explain clearly on what's the best way to reinstall - Should I delete all partitions and then start? OR should I keep the SYSTEM_DRV partition - i.e. is this partition mandatory for BOOT OR does the Windows installation create its own BOOT partition?!!
Also, my current Partition two is non readable, and that's what contains the Windows folder.
Chkdsk ran for 5 days, and while I wasn't observing, the system rebooted - I want to know if it happens after Chkdsk?

Would formatting or wiping my Partition two - solve the corruption issue? Currently this partition is non-readable even from the command prompt.

I have searched so many threads and can NOT find anyone explain this clearly. So, if you don't know a simple answer, please don't respond.
All data backup has already been done.

If you have your data backed up then you can wipe all partitions without any worries, however make sure your HDD is not failing.

Read this first though: Clean Reinstall - Factory OEM Windows 7
There is a section for Lenovo users at the end of tutorial.

As far as I know:
The 1st partition is needed only if you want to use BitLocker BitLocker - Wikipedia, the free encyclopedia
The 2nd is where windows was installed, C: as you would see normally
The 3rd partition should contain the drivers that was installed
The 4th partition - I have no idea about

You can download a live Linux CD/DVD and burn it/create bootable USB and see it's contents, or rather you should be able to!

Have your wireless/Ethernet drivers at hand in case they are not found with Win 7 installation. Rest you can get from Windows Update and the rest from Lenovo support site (detailed in the tutorial)

I hope this helps.

Do you know if the clean Windows installation would create a similar 200MB boot partition?
Or is it gonna put the BOOT files under the same partition as the Windows files?

Thanks

If you let the installer do the partitioning than a 100MB system reserved partition will be created and the boot files will be installed there. There is really no need for that partition.

Read the tutorial, most of your questions will be answered. Whatever is left in your mind, feel free to ask of course :)

From the tutorial:

Boot the Windows 7 installer, choose Custom Install, then at the Drive Selection screen access the Drive Options (Advanced) to Delete all partitions not needed, repartition and format as shown in Steps 7 and 8 of Clean Install Windows 7 which illustrated steps will guide you through actual install.

Thanks for that, the Clean Install guide answered that question.
One more thing before I do this, Would reinstalling Win 7 as in the guide (i.e. deleting all partitions - which does the formatting automatically, I assume) - solve the corruption (or non-readable partition) issue?
Currently this 890G partition is non-readable from the command prompt - i.e if I type in D: on the command prompt (from recovery options), it says I/O Read Error.
Parted Magic can NOT mount this partition, and asks me to run a chkdsk again. The health of this drive is in red. So, should I try the Windows reinstall on this drive? All other partitions 1,3, and 4 are mountable on Parted Magic, and readable from the command prompt.

Thanks.

Hmm, I am not very proficient in this type of issues and I don't want to mislead you.

As I have said you should make sure the drive is healthy.

Perhaps best action would be to open a new thread in "Hardware & Devices" so experts frequenting that section advice you better.

Test the drive with the maker's HD Diagnostic.

If the drive is failing, then I'd replace it with an SSD which is the best upgrade you can get now - even better than buying a new high end PC without one. I have one in my Lenovo laptop which is lighning fast.

Stick with the tutorial for reinstall and you will get and keep a perfect install just like 1.5 million others who have used it without a single complaint.