Do not delete Thumbs.db as this file was always there - this since you changed settings to show hidden files and folders.
So, hide your hidden files and folders again, in the same way as I described previously (how to reveal them).
Glad I could help.
Please read my Prevention page with lots of info and tips how to prevent this in the future.
And if you want to improve speed/system performance after malware removal, take a look here.
Extra note: Make sure your programs are up to date - because older versions may contain Security Leaks. To find out what programs need to be updated, please run the Secunia Software Inspector Scan.
Happy Surfing again!