Fix windows 7 missing hard drive space

My computer run Windows Xp. But after installing windows 7 in dual boot, I found the hard drive partition of windows XP is missing. How to fix it? Show up hard drive in windows 7.

1. Click start button --> type diskmgmt.msc in the search box --> press Enter to open the Disk Management.
2. Now select Drive without any drive letter in the interface --> Right Click --> Select “Change Drive Letter and Paths”
3. "Add button in the next menu" --> Choosing "Assign the following drive letter" --> pick a drive letter, such as "k" --> Click ok.

Now you can find the missing drive of windows XP or Vista.