Disk near capacity

Computer C drive almost full. Started running slow 2 days ago. Got notice yesterday. I can only account for about 25G used - between programs, e-mail and windows. Have a 74.5G drive. Figured had to have a virus or something. Have used Microsoft Security Essentials, CCCleaner, Malwarebytes and Advanced System care 5. No viruses or malware found. It did give me a little more space but not much. Also the computer is send out an e-mail over and over. Any suggestions on what else I can do?

 

Start a new thread in the Malware Removal Forum after you have read and followed the instructions in this post. Then attach your logs.