[problems100]

with xp I'm finding that attempting to use microsoft's own clean-up scan (from their website) results in the computer rebooting part way through the scan. I also have AVG antivirus free edition installed and this refuses to complete scheduled computer scans; again, by rebooting part way through. Is there another check I can do to find out if there is anything sinister present? Any suggestions welcome.

[lunarlander]

You can try the online scanners: Panda Activescan, Bitdefender Online Scanner, and TrendMicro Housecall.

[perfume]

Dear problems100,
Just to add to lunarlander's post, you may try scanning with Malwarebytes Anti-Malware(free)! You sure have a problem on hand, and you SHOULD TRY A rootkit scan, using the RootKitRevealer from sysinternals which you can download from: http://technet.microsoft.com/en-us/s.../bb897445.aspx

[problems100]

Thanks, lunarlander and perfume, for your quick responses. Here is a summary of what happened when I followed your advice.
Trendmicro, bitdefender and panda all failed to download satisfactorily for unknown reasons. I performed the malware on-line scan and it showed up a number of potential problems, some it characterised as serious. However, when I downloaded the free version and used it, far fewer problems seemed to be detected but I deleted them anyway. Using rootkit revealer results in the system rebooting after 5 seconds of scanning, which is ominous. After all this, the AVG scan still doesn't go through. The question I'm left with is - since the computer appears to be working OK otherwise, should I let sleeping dogs lie or chase them around a bit more?

[Cookiegal]

The General Security forum is only for general questions regarding security software and things of that nature but not for actually removing malware as we have qualified helpers who are the only members who are authorized to assist with those matters. You can easily identify them as they have either a gold or blue shield beside their usernames. Please refer to this excerpt from the rules:

http://www.techguy.org/rules.html

Log Analysis/Malware Removal - In order to ensure that advice given to users is consistent and of the highest quality, those who wish to assist with security related matters must first graduate from one of the malware boot camp training universities or be approved by the administration as already being qualified. Those authorized to help with malware issues have a gold shield next to their name and authorized malware removal trainees have a blue shield next to their names. If you'd like to participate in a training program, please contact a Moderator or see this article.

I'm going to close this thread and ask you to repost in the Malware Removal & HijackThis Logs forum for the proper assistance.