Windows 7 Suddenly Disappeared

I run a brand new macbook pro lion os x 10.7

I bought windows 7, and using bootcamp, successfully installed it onto my computer, so I could run either windows 7 or mac upon start up.

In the partition, I initially gave windows 7 50gb of space, and then gave mac the rest of the space. Later, I realized I need more space for windows 7, so I went into disk utility in mac and opened up 50 gb of free space in bootcamp (I went under the "partition" tab, and changed the number of mac gb to a smaller number, and then applied it). Then, I restarted into Windows 7. After I did that, I downloaded "MiniTool PartitionWizard Home Edition v7.1", which allowed windows 7 to occupy that free space. This appeared to work fine- windows 7 got more space, and nothing strange happened.

THEN, after that, I was prompted by windows to free up even more disk space. So, I tried to do the same thing again. But this time, after I opened up more space in the disk utility of mac (50gb more) and restarted, windows 7 was no longer there. It is not present at all, anywhere. It's completely disappeared.

What should I do? Do I have to reinstall windows? What happened, and how can I prevent this in the future? Also, for future reference, what is the best way to change the bootcamp partition if it needs to be changed after initial installation?

Thank you for your time and effort in helping me with my problem!

Could someone PLEASE help me? Or at least tell me what you would do in my situation? Reinstall windows 7 or not? I would be very grateful for any advice at all.

The Windows 7 partition just didn't disappear, but what I suspect happened is that you somehow overwrote or damaged the Windows 7 partition information. Using Disk Utility to shift the partition size was not a good idea as that usually leads to trouble.

You're probably looking at reinstalling Windows 7. Use the Boot Camp assistant to remove the Windows 7 partition if possible. If it refuses, use Disk Utility to remove it and to restore your OS X to one partition.

To expand and or contract a Windows partition that was created with Boot Camp, the best tool to use is "CampTune" from Paragon Software.