Looks like you have ran out of space on the Hard Drive. 17% of the Physical Drive should be left empty to enable the Drive to be Defragmented and enough for Pagefile manipulation.
Download this and create your CD. Boot from the CD and remove some of your files to give the Drive a bit more space. Work through the Temp folders first, then delete any unnecessesary files.
http://www.ultimatebootcd.com/
When you get up and running again Backup and burn your Data to CD/DVD. Remove any unnecessesary Programs and files.
I don't think that you have an infection but here is a link anyway.
W32.Sasser Removal Tool
http://www.symantec.com/security_response/writeup.jsp?docid=2004-050114-1706-99