boot time scanner vs. scaner of simple user interface?

Avast Free Antivirus / Premium Security
1

I have performed boot time scanner yesterday since a lot of viruses was found on my friend system. All malwares were moved into chest.

Then, return to windows, I performed full scan with options: ‘normal scan sensitivity’ plus ‘scan archive files’. Immediately, it caught some viruses in a compressed .exe file.

I wondered why the boot time scaner did not catch them?

In order to verify it, I have moved the virus archive file (command.exe) into c:\fff folder and then scheduled a new boot time scan again. (see fig 1)(‘scan archive files’ option was checked!)

The boot time scan got the results:

08/14/2006 01:20
Scan of C:\fff

Number of searched folders: 1
Number of tested files: 1
Number of infected files: 0

you may see the results of simple user interface from fig. 2 ( captured from virus chest)

2

The boot-time scanner doesn’t support all the archives the “ordinary” Windows version does.
The file in question seems to be an SFX archive… could be RAR, maybe CAB… the boot-time scanner doesn’t support these.

3

Hello,
Could you please summarize the difference between Boot-time scanner and On-demand scanner ?

Thanks in advance

4

It seems a rar SFX since it can be extracted by winrar. Maybe~~