Moved to Malware Discussion > Home User Assistance as a better spot.
Exploit!Win32/pdfjsc according to Microsoft "Win32/Pdfjsc are a family of malicious PDF files that exploit vulnerabilities in Adobe Acrobat and Adobe Reader.
The vulnerabilities allow malware to download and run arbitrary files." It's not malware in itself but it could allow some in.
So I suggest that you check your system for updates, especially to browsers (all if them including Internet Explorer even if you don't use it) and their add-ons.
Make sure Adobe products especially are updated.
The Security Scanner looks for holes in your system, not just malware and in any case different brands of scanner often find different possible threats.
Try running Stinger and maybe Malwarebytes Free, both linked in the last link in my signature below.
Great thanks for the help. I actually did you what you said and found that it was attached to an old Adobe PDF file.
That's good. All the best ;-)