Assalam o Alaikum!

Meri System ki
C:\ Drive main XP or
D:\ Drive main Win7 installed hain..
Mujhey Windows xp dobara install karni hay lekin maslah yeh hay ke aisa karnay se windows 7 ki boot files remove hojayengi or woh load nahi hogi..
To iske liye mujhey kaunsi files ka backup rakhna hoga jis se xp dobara karnay ke baad main paste kardoon to dono windows dobara se kaam karain.. ?