I am having this same problem. This is a BIG TIME problem for me. :'(
1. First [before uninstall & re-install] – I tried to just restart the service.
Windows Dialog said: "Could not start the Avast antiVirus service on the local computer."
2. I uninstalled old version, downloaded latest, re-installed.
Install worked and ran the mini-scan.
3. Clicked Finish on the install.
-Avast came up and said i was protected.
-Then after about a minute, a Windows Dialog came up and said Windows couldn't
execute an instruction at some address.
-After that the system tray icon showed UNPROTECTED
Avast UI said "avast service is stopped"
4. I clicked "start program" then "Fix Now"
- nothing happened
5. I went to
That is because the Microsoft Management Consule and smss.exe stopped the process due to unsafe and unknown conditions, might also be linked to some issues with the latest change that would update the VPS and for XP users, it causes a BSoD Stop Error, apparently seems the NT 5.0 subsystem is getting close to loosing compatablity due to security problems as of late, this affects 2000 and XP, more reasons Vista and Windows 7 have more security than any NT 5.0 Kernel Mode sub system.
And I knew it was smss.exe when I was currently using WinDBG to diagnosed the problem, the CPU usage to smss.exe was being used from 5% to 20% knowing it wanted to terminate the service because of some windows Zero Day flaw that was detected in the crash,
This exception may be expected and handled.
eax=00000000 ebx=00000000 ecx=7ffa4000 edx=07bd9898 esi=00000000 edi=00000000
eip=00000000 esp=050ffc18 ebp=050ffc60 iopl=0 nv up ei pl nz ac po nc
cs=001b ss=0023 ds=0023 es=0023 fs=003b gs=0000 efl=00010212
00000000 ?? ??? <--- Zero-Day offset crash
The offsets point to ntdll.dll and smss.exe as being the culprits on Windows 2000 which means a fatal flaw has been found and these 2 files can no longer support this anti-virus program, also online anti-virus scanners are being not accepted eaither due to these 2 files, and it is not malware issues, most likely it is as one of the Tech people said on here "End of Life" issues.
And here is a similar thread to this too,
http://forum.avast.com/index.php?topic=82702.0