What is the first method to increase the size of a system-partition on Windows 7 ? The disk does not have any un-partitioned space.
I've tried GParted and it's damn slow :X
Resizing a partition that's next to another partition is very slow, IIRC because basically the whole partition's worth of data needs to be moved around. Set up GParted overnight with the operations you want queued, and it should be done by morning even if the drive in question is huge.
Also, check out SequoiaView if you want to trim unnecessary files from the partition - it shows the file types and sizes by different sized colored squares, so if you've accidentally gotten a bunch of media files on the OS partition, it'll be quick to figure out. Freeware, http://w3.win.tue.nl/nl/onderzoek/onderzoek_informatica/visualization/sequoiaview//
I would start with TreeSize it is a free program that will tell you what is all being used as far as space. Maybe you can determine what is so large and clean it up from there.
Another good tool is EaseUS to help with the partioning portion.