AVIRA: Over-Enthusiastic Hueristics?

I have no reason to suspect that this Win7 PC is infected.
I always have realtime protection and updates running with Avira & Malwarebytes
This is what I get when I scan with Avira. (Heuristics set to default - medium)
I didn't run any repairs.

C:\Windows\regedit.exe
  [DETECTION] Contains suspicious code HEUR/Modified.SystemFile
  [NOTE]      The detection was classified as suspicious.
  [WARNING]   The file was ignored.

Ditto for these ......
C:\Windows\system32\ntvdm.exe
C:\Windows\system32\reg.exe
C:\Windows\system32\userinit.exe
C:\Windows\system32\rundll32.exe
C:\Windows\system32\regsvr32.exe
C:\Windows\system32\mshtml.dll
C:\Windows\system32\dnsapi.dll
C:\Windows\system32\d3d9.dll
C:\Windows\system32\msvcrt.dll
C:\Windows\system32\aclui.dll
C:\Windows\system32\dsound.dll
C:\Windows\system32\imm32.dll
C:\Windows\system32\ctfmon.exe
C:\Windows\system32\drivers\beep.sys
C:\Windows\system32\kernel32.DLL
C:\Windows\system32\gdi32.DLL
C:\Windows\system32\user32.DLL
C:\Windows\system32\advapi32.DLL
C:\Windows\system32\wuauclt.exe
C:\Windows\system32\alg.exe
C:\Windows\system32\spoolsv.exe
C:\Windows\system32\csrss.exe
C:\Windows\system32\lsass.exe
C:\Windows\system32\services.exe
C:\Windows\system32\ws2_32.DLL
C:\Windows\system32\wsock32.DLL
C:\Windows\system32\wininet.DLL
C:\Windows\system32\smss.exe
C:\Windows\explorer.exe
C:\Windows\system32\winlogon.exe
C:\Windows\system32\svchost.exe

Can I believe any of this ?