One thing you can do is run Disk Cleanup and or turn system restore off to free up space. I'd probably turn system restore back on so you have at least one restore point to bail you out if you screw up. Turning windows features off just hides them so that probably won't help. Part of the problem in your case is all of the files for every feature of windows 7 are there. Some features are just disabled depending on which version you install. Using anytime upgrade just enables the features for a higher version. You probably can't increase your system partition unless there is unallocated space to expand it into. You would likely have to reduce another partition to free up space first. Even then it may have to be continuous space to be usable, be adjacent to the partition you want to expand.