Resizing your Windows partition:
Boot into Windows, and back everything up. Defrag the drive. Run scandisk, the defrag again, just for good measure. Boot into Mandrake, make sure your Windows drive is *NOT* mounted
, and try to resize it using the partitioning tool. If it still fails, you might have an unrecoverable error, and the only recourse will be to *delete* the partition, and recreate it at the size you want.
Resizing your Linux partition(s):
Boot into Linux, and back everything up. Now the fun part. You can't resize a partition that is currently mounted, but you have to have the partition mounted to run the partition tool! (or anything else, for that matter.)
Personally, I use Knoppix as a rescue CD for handling these kinds of things. However, you might be able to boot your installation CD, and step through the first steps to the partitioning phase, at which point you should be able to resize them ("Custom Partitioning"). I have never tried this, so I can't really vouch for it. Maybe another poster has better information.