After I have update Firefox I have scan again with MAB and it found and quarantine 2 new infections

:
Malwarebytes' Anti-Malware 1.50
www.malwarebytes.orgDatabase version: 5214
Windows 5.1.2600 Service Pack 3
Internet Explorer 8.0.6001.18702
01/12/2010 18.47.16
mbam-log-2010-12-01 (18-47-16).txt
Scan type: Full scan (C:\|)
Objects scanned: 262128
Time elapsed: 1 hour(s), 16 minute(s), 47 second(s)
Memory Processes Infected: 0
Memory Modules Infected: 0
Registry Keys Infected: 0
Registry Values Infected: 0
Registry Data Items Infected: 2
Folders Infected: 0
Files Infected: 0
Memory Processes Infected:
(No malicious items detected)
Memory Modules Infected:
(No malicious items detected)
Registry Keys Infected:
(No malicious items detected)
Registry Values Infected:
(No malicious items detected)
Registry Data Items Infected:
HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Start_ShowMyDocs (Hijack.StartMenu) -> Bad: (0) Good: (1) -> Quarantined and deleted successfully.
HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Start_ShowHelp (Hijack.StartMenu) -> Bad: (0) Good: (1) -> Quarantined and deleted successfully.
Folders Infected:
(No malicious items detected)
Files Infected:
(No malicious items detected)
Now I'm quite sure which I have a virus on my PC.