Many members have used this software with success
Free Download Magic Partition Manager Software - Partition Wizard Online
I think the point here is that you are trying to expand the wrong volume, and not to expand the 100mb partition, but one of the others. Please also try on drive letter E:\. No need to go ahead with the resizing, just see if it allows you to:
a) resize any partition other than the one shown in the screenshot (100mb)
b) See if it allows you to resize partition E:\
Thanks!
Richard
Are you referring to the 100 mb?
Solved What's on that 100MB partition? Can I delete it? - Windows 7 Forums