Should I reformat Windows partition before re-installing?

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I have Win 7 Home Premium SP1 on Dell Inspiron 17R 5720, 4 GB RAM.

I have Windows and programs on C: partition. Data is on E: partition.

I want to do a clean re-install of Win 7 SP1, and leave all the data on E:

My question is: Should I format the C: partition before re-install?

I saw this post by Alejandro85 here:

Delete or format C drive when reinstalling Windows?

Alejandro85 said:

There is no need to delete (or even format) any partition to reinstall Windows.

My problem is that I'm so old I remember when disks used to frequently develop bad sectors during use. These bad sectors were marked in the FAT during formatting, so that they would not be used by DOS.

Is this no longer true? :)

Thanks.
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While not strictly necessary it is always a good idea to format the partition. This is normally done as part of the install process.
Again, while not strictly necessary it is a good idea to delete all system, but not data partitions. Disconnecting other drives is also highly recommended. These things simplify the installation and avoid unpleasant surprises if things proceed different than anticipated.

And always do a backup of your data before proceeding. Never rely on some Windows feature to do this for you. Many people have made some mistake and end up formatting and installing the OS on the wrong partition or drive. Even experts make mistakes. But experienced computer users anticipate that problems may occur and prepare accordingly (with backups).

We never bother. Just put the image over the top or if disk install, custom allow this option so its all im one job format / install in steps of cause

really if you can only have the target HDD connected and clean all is best if possible

FDisk
format should be enough thou

What is the purpose of wanting to re-install your Windows 7 system.

Do take note that is to install using OEM Recovery disk, there is this 1st partition for Boot, which is hidden.

That is why in post #2 @ThrashZone recommended should be done.

If you find that your system is slow, then do "disk defragmenter" the C:\ drive.
But do go to C:\Windows\Temp to delete all these useless files, just skip the files that cannot be deleted.
Also, go to C:\Users\Eric\AppData\Local\Temp <replace Eric to your User name> and deleted as mentioned above.
Finally then run the Disk Defragmenter.

Any re-install will required you to re-install other program, application, etc

Finally, you have to do Windows updates which may take a long time and sometimes it is very slow like not working, But it is work in-progress.
For short-cut on this do refer to post #2 @ThrashZone to show you how.

Your decision, as these replies are of several options for you to decide.