Resently, i downloaded some .exe files and i got messages saying error, sys32 nonvalid application (or something like that, i got a french version of windows), but it did that to only the .exe files i download.
I also noticed a file that appeared in windows\temp named sys32 and in that file was a huge number (600 something megabytes worth)of downloaders which filled the rest of my c drive. need help... :-(