Hello ankitkr and welcome to Seven Forums.
Couple of questions. When you upgraded did you do a clean install (format the entire hard drive), clean install (format only the C: partition containing windows 7), or something else like dual boot? Do you know if your Lenovo still has a hidden recovery partition containing the original Windows 7 and other factory installed software? A screenshot of your Disk Management would be helpful to see how your hard drive is configured and what you have to work with.
How To Access Disk Management in Windows 7
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