what i wonder is after writing partition table for first time will i again be able to find those other lost paritions ??
Yes, TestDisk searchs your partition looking for any boot sectors and their backup.
Partitions will be listed and you should be able to register them in your partition table again.
You always have to register all partitions in your partition table.
If one ist not registered, this partition is not available.
You can only have 3 primary and 1 extended for logical partitions.
If you have 4 primary partitions, you will be not able to create an extended one.
1: P dell utility
2: P OS
3: * System Reserved
4: P Win7
You've already 4 partitions.
So it's not possible to create an extended partition anymore.
That's why I suggested to install Win7 on a single partition, without that "System Reserved" partition
Like in my previous post;
Consider to reinstall Win 7.
Delete your System Reserved partition, win7 partition and Anrun, Others and Multimedia-Partitions also (I assume that your 3 logical partitions only created and do not contain data).
Create one partition using gparted.
Install Win 7 on that partition, without creating any other partition.
After installing Win7 create your extended partition using diskpart.
http://answers.microsoft.com/en-us/wind ... c816e62faf
Create your logical partitions as you like it.
Have look to create multoboot for Win7 and Ubuntu.
Load it down for non commercial use!
Otherwise have a look to Linux-bootmanager Grub.
You should have a backup of all your important data
Your plan to backup your data is a good idea.
Do that first and backup all data!
But think, to make a complete backup of all your data and reinstalling Windows without using any "System Reserved"-partition.
So you have on partition less in your partition table und you would be able to create an extended partition.
In an extended partition, you can create as much logical partitions as you like to.
But is limited to available drive letter or alphabet.