Bizarre Downloading Problem

[Tomm]

Picture the scene: I'm downloading something off rapidshare, it says 5mins remaining, so I read a book while I'm waiting. After 10 mins or so, I look back and the download hasn't finished. In fact it still says 5 minutes and doesn't seem to have changed since the last time I looked. Then I move the mouse and it starts downloading again. Repeat this a few times until I realise that it's only downloading when I'm using the computer / moving the mouse / typing. When I'm away from the keyboard, the download stops. It also won't download when Firefox is in the background.

I've tried a different website, and that's the same.

There isn't a problem with internet explorer (that downloads things just fine)

I've had a looked on task manager and can't see anything too unusual in the processes section, but the network tab confirms my suspicions - the internet connection is only being used when I'm at the keyboard or moving the mouse (with Firefox)

Apart from the fact that this is really weird, I'm a bit concerned that I've got some sort of Malware on board. I've done an AVG scan but that didn't show anything. Any ideas?

My spec: Windows XP. Firefox 3.6. Really old AMD Athlon 3200+.

[rocktrials]

given malware antibytes a try?

[Bronz]

I'd run an Avast (free) boot scan. This found viruses on my missus' PC that Norton and ESET had no idea about.

[anzo]

It sounds like you have obtained some rather clever Malware there...At the end of the day, a scan can only pick up what it's told to look for, by no means does an unsuccessful scan mean that your computer is clean.

For sakes sake, I'd clear out the Temporary Internet Files, Clean Up the downloads in Firefox and try it.

Failing that, perhaps reinstall FireFox and try again,

Failing that you're probably looking at reinstalling XP for a quick answer to this - you could spend many weeks trying to find the cause, or simply get rid of it all in a couple of hours.

[MadManMike]

ComboFix.

That's rescued my PC a few times!

[Tomm]

I think it was some kind of malware thing, but I'm not sure what. Interestingly I noticed that it was doing the same "pause" thing even on simply loading websites. Weird.

I did these things:

Delete cookies / temporary internet files

http://download.cnet.com/Malwarebytes-Anti-Malware/3000-8022_4-10804572.html?tag=mncol

http://www.combofix.org/

http://download.cnet.com/Advanced-SystemCare-Free/3000-2086_4-10407614.html?tag=mncol

And the problem seems to have gone away