I agree Greenknight, the size of HouseCall's definition file alone is near the size of a full-featured antivirus program, HouseCall stopped working on my system when they added spyware scanning. The only online antivirus I now use is Microsoft Windows Live Safety Center which scans for viruses and spyware, and it currently doesn't require some 8MB definition file like HouseCall which would take 30 or so minutes to download on my dial-up connection.
I tried that MSWLSC scan, it was also pretty slow. But if it works well, that's what's most important (and I have no way to tell for sure). I do like the way it can scan for open ports. If it can actually close the open ports, that will provide users of the XP firewall something that's been lacking up to now.
I ran a BitDefender online scan the next night, also a long process (2 hrs 35 min to update and scan). It found 2 suspicious files the MS scan didn't, but they might have been false positives. I had set the option to have it ask me for a prompt if it couldn't heal the files, but instead it just deleted them. So I can't check those files to find out if there was anything really there.
for about a month i had been having trouble with accessing the houscall scan. the page would hang up when linking to the european site. i tried diferent things to trouble shoot the problem, i even made a post at Lunarsoft about this. untill i was even having trouble acessing the MS update page. with RRidgley help that problem was solved. turns out that Norton firewall was blocking access to MS updates. on a hunch i decided to try Houscall again with Norton turned off and i was able to complete a full scan. i am a little confussed with the result as Housecall found 1 infected item. it listed the Maxthon brower as grayware.
I tried that MSWLSC scan, it was also pretty slow.
The only way to speed up those free online virus scans is to disable your resident/real-time protection in your installed antivirus, which is what I've been doing for 5+ years when using online virus scanning services. Now if I leave eTrust EZ Antivirus' real-time protection on my scan at MSWLSC would take at least 25% longer, it's currently at about 28 minutes to scan, well it actually takes approximately the same amount of time to scan my whole system as eTrust EZ Antivirus does.
I do turn of my resident AV when doing those scans (unless I forget). It's good that you brought that up, though. Some people might not be aware of that. When running any other virus scanner, whether online or not, you should shut down your resident AV protection.