LAN virus disabling Files and Printer Sharing & Sound Card unless you restart

Hi,
I am a software developer myself and I suggest using Avast Antivirus everywhere. The only security system for me as a developer after testing lots of other antiviruses was only Avast.
In our company’s LAN, I use Avast for clients with manual updates once in two days. In order to prevent autorun viruses of Mass Storage Devices like USB Flashes, I use Naevious USB Antivirus too with Avast. The clients are Windows XP SP3.
Last week a gust to the company inserted her flash memory to some clients. There was a virus in that which none Avast nor other antiviruses detected when copying. The first symptom was locking folder when moving or removing folders. I used Unlocker to find out that for example when deleting E:\folder\ the file system E:\folder\services.exe which does not exist or is in processes locks folder for some minutes. After first reboot there is nothing to be detected. After a while using your PC, theme service of windows restarts automatically (The start bar of windows goes to Classic mode then again back to Luna theme). After this event Avast may detect a Win32 threat in I think in C:\Windows\System32\x (I forgot the name because I put a tick to do the delete process everytime without showing it, but I remember that x)
I reformatted and reinstalled windows for some clients but they got effected again via LAN. The point is this which causes lots of problems for me as network administrator: After theme service of windows restarts, the LAN is not accessible but you can ping other clients or even LAN based softwares and network monitoring tools all work perfectly but Files and Printer Sharing gets disabled. You can not access shared folders or go to some clients like \client\ … or use network printers. The other thing is disabling Sound card which prevents sound of playing media. When you reboot, all this problems get fixed and there is no virus detected. Please help. Personnel does not accept rebooting times and times everyday.

Thanks a lot in advance

welcome to the forum. it’s better to send an infection to the chest then deleting it. if you delete it you have no options left if it is an false threat.

no offense but why do you manually update avast when it can update itself automatically without disturb the user.

good think of you there to run usb antivirus to stop spreading usb virus.

another good program to run with avast is malwarebytes. http://www.malwarebytes.org/ if you still have problem with that infection or still think you need an section opinion if you computer are infected.

hope this will keep you lite better safe in the wild. keep up your job of keeping your computer safe and write back if you need more help.