Verecno is a malware classified as worm. This malware infection most possibly dropped by other malware or as a file downloaded by drive-by download technique when users visiting malicious sites.

Windows Defender and Microsoft Security Essential will detect this virus as Worm:Win32/Verecno.A

The verecno worm drops the following files:

• C:\Google\Autoit3.exe
• C:\Google\Google.lnk
• C:\Google\Windowsupdate.lnk
• C:\Google\GoogleUpdate.lnk
• C:\Google\GoogleUpdate.a3x
• %User Startup%\GoogleUpdate.lnk
• %User Startup%\GoogleUpdate.a3x
• %User Startup%\WindowsUpdate.lnk
• {removable drive letter}:\Hot.lnk
• {removable drive letter}:\Movies.lnk
• {removable drive letter}:\My Games.lnk
• {removable drive letter}:\My Pictuers.lnk
• {removable drive letter}:\My Videos.lnk

File size 133.4 KB (136649 bytes)

Question

Error C:\Google\googleupdate.a3x" during Windows startup

It appears the following error at the start up. I'm using Windows 7 ultimate.                                        Line 0 (File"C:\Google\googleupdate.a3x"): please help me.
  

Answer 

Verecno is a malware classified as worm. Each time at Windows startup the Line 0 (File"C:\Google\googleupdate.a3x") error message window will appear because of this worm removed by anti-malware installed in the system. But malicious registry entry created by malware to auto-start & run itself on every reboot that entry still be present that’s why getting this error on system startup.
Windows Defender and MSE will detect this virus as Worm:Win32/Verecno.A
googleupdate.a3x is malicious file dropped by verecno malware. Read more about verecno malware removal and how to fix googleupdate error http://www.geekzsupport.com/worm-verecno-remove-googleupdate-startup-error/
Follow below steps to get rid of this error,

1. Press Win+r, type regedit and enter.
2. Now press ctrl+f, type googleupdate.lnk and hit find.
3. Windows registry search and show detect entries under HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run and HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run path just delete it and hit find to found next.
4. Similarly search with autoit3.exe, windowsupdate.lnk, googleupdate.a3x