BleepingComputer.com: Low Disk Space (Drive C) of less than 500mb

You have to look in each folder...and have some idea of what should be in the Application Data folders.

On my systems, the contents of any AD folder listed for any user...is less than 200MB. If any of your Application Data folders reflects anything other than that, I'd say that's a target for inspection/review.

I believe that emails may use those folders as a default storage location, http://www.insideoe.com/files/store.htm. I have moved my message store to a different drive, so my saved emails do not clutter up my system/boot partition.

Louis

I agree with Louis, in that the mail store is the only thing I can think of that will increase over time. Do be aware that, according to the article Louis linked to, you can't move the mail store to a removable drive. If your D drive is an internal hard drive then you are OK, but an alternative is to archive your email to CD or other removable drive. It isn't as cheap and easy to do as just moving the store since you have to extract the emails from the .dbx/folder files if you want to access them later. The only tool I know of that will do that, DBXtract, is no longer free. I am about to go thru this process myself--when completed I can just delete all those old emails from years ago and still have access to the ones I want to keep.

Another advantage to this is that the larger the .dbx files get the more likely they are to be corrupt.

As far as System Restore, purging it, as you have done, will only free up disk space temporarily. SR has a certain amount of disk space set aside for it, so it wouldn't account for an increased disk usage over time and it will delete old restore points on a first in first out basis once the space set aside for it is reached. In fact it will shut itself down when you run out of disk space. To free up some space on a permanent basis, adjust the disk space usage of SR. As mentioned in that article, 1 GB should be plenty--restoring past two or three days isn't really of much use. You might go lower than that but be careful, with no restore disks I recommend you have a good working SR available to you.

I don't use outlook (just gmail) so would my mail folders fill up?

I'm having similar problems. All the free space has been eaten up again. I'm not worried it may be malware. I'm experiencing problems getting windows to install uploads, I have a weird IE popup/wave volume muting problem that seems to be going around now and got the blue screen of death a few times. I posted about the possible malware problems here:

http://www.bleepingcomputer.com/forums/topic331515.html

Seems like the malware experts are fairly busy now so I will wait and update here when I resolve that as well.