Local Disk C

Certain Vundo / Virtumonde variants can create many many files in your C drive (or system drive) slowly eating away at your disk space. These are easily identified because they will look like:

pos*.tmp

The * indicates a random number.

Other then these files I wouldn't go about in the C drive deleting files.

The best thing to do is run an anti-malware application so it can weed out all the files that don't belong, but because you are so low on disk space this may not be possible. If you can install, update and run Malwarebytes' Anti-Malware:

http://majorgeeks.com/Malwarebytes [...] d5756.html

You could also look at other ways to free up disk space. The most obvious solution is to move photos, music, documents and movies to external media. I would do this regardless as only having 2% of free space is dangerously low and you risk losing everything if worst comes to worst.