Runtime error! Virus or what?

[system]

I have a problem. When I try to access any folder of Local Disk D:\ it shows me:

Runtime Error!
Program: C:\WINDOWS\explorer.exe
This application has requested the Runtime to terminate it in as unusual way. etc.

I have scanned the whole system using Avast. It found a decompression bomb ( it ends …and Serial.exe[UPX].

What is that? Is this a virus or what? What happened to my computer? ??? I hope I won’t lose any files that are in D:? What should I do?

[Lisandro]

@poubetnetai post:1

I have a problem. When I try to access any folder of Local Disk D:\ it shows me:

Runtime Error!
Program: C:\WINDOWS\explorer.exe
This application has requested the Runtime to terminate it in as unusual way. etc.

Please check the folder \data\log
Are there any files called unpXXXX there (where XXXX is a random number)?
If so, send them to vlk (at) avast.com
They may contain more information about the problem (maybe a link to this thread).

@poubetnetai post:1

I have scanned the whole system using Avast. It found a decompression bomb ( it ends …and Serial.exe[UPX].
What is that? Is this a virus or what? What happened to my computer? ??? I hope I won’t lose any files that are in D:? What should I do?

Decompression bomb is a file that may be rather small, but decompresses to an enormous amount of data (when processed as a packed archive). Such file are not malicious per se, but they may block an antivirus program when it tries to scan them.
This kind of files is rather hard to detect (and avoid) precisely - so, it is possible that there are some false alarms. It’s not a big problem in this case, however - the “decompression bomb” announcement actually means something like “The file has a very high, maybe even suspicious, compression ratio and the AV is not going to scan the archive content”.

I’d suggest to ignore these files.
But you can change values into avast4.ini file to configure how avast should work with these files.
Click ‘Settings’ in my signature for more info

[system]

@Tech post:2

Please check the folder \data\log
Are there any files called unpXXXX there (where XXXX is a random number)?
If so, send them to vlk (at) avast.com
They may contain more information about the problem (maybe a link to this thread).

I’d suggest to ignore these files.
But you can change values into avast4.ini file to configure how avast should work with these files.
Click ‘Settings’ in my signature for more info

Thanks a lot for advices.
And, I’ve sent these unpXXX files.
But I can’t still access my folders in normal way. I can do this only using other programs e.g. Mozilla Firefox, open using 'Run… ', or Browse them normally by Nero or other.
Well, I hope I’ll find that something that makes me nervous about.
Anyway, thanks again.

[Lisandro]

@poubetnetai post:3

But I can’t still access my folders in normal way.

Did you run avast at boot time?
Start avast! > Right click the skin > Schedule a boot-time scanning.
Select for scanning archives.
Boot.

It will also be good if you:

1. Disable System Restore on Windows XP: http://support.microsoft.com/default.aspx?scid=kb;[LN];310405
2. Clean your temporary files. You can use the Windows Advanced Care features for that.
3. Schedule a boot time scanning with avast. Start avast! > Right click the skin > Schedule a boot-time scanning. Select for scanning archives. Boot.
4. Use a-squared, Free AVG Antispyware or SUPERantispyware (trojan removers).

After being clean, use the immunization of [url=SpywareBlaster or, which is better, the Windows Advanced Care features of spyware/adware cleaning and removal.