How to reinstall windows 7 in Dell xps 15 (L502X)

[virajqs]

Hi,

I'm using Dell xps 15 (L502X) Laptop with original windows 7.However i installed windows 8 on it and now i want to reinstall windows 7 again.
How to do it without deleting my data,files etc..
My laptop has three partitions in hard drive.

 

[dakshinasd]

Do you have a recovery image with original Windows 7? or is it purchased separately?

 

[virajqs]

Do you have a recovery image with original Windows 7? or is it purchased separately?

Yes I have a recovery image..