How Do I Fromat A Partition With Os And Reload Os In The Same Partition

Really depends on what OS you had in mind.
Part of the install process is a format of the selected partition.
Simply boot to the CD and follow the on screen prompts.

I use the windows xp disk

I boot from the xp disk and you must delete any partitions just follow the screen.

It will tell you exactly how much space you have on your hard disk - Example 76521

Click C to create a partition and amount 61216
Move arrow down
Click C again to create another partition 15304

This means your partition is split 80 % for c drive and 20% for d drive

Then you continue installing xp by highlighting the 61216 partition and click enter.


These amounts are not accurate - its only an example

And keep in mind formatting means what was there originally is gone. If your hard drive has XP on it now, formatting/repartitioning will erase everything. Installing XP again isn't "reloading" anything, it's fresh new software on a fresh newly formatted drive.

Remember to save off any data you want protected before you do this.