This is a useful collection of free external online virus scans.
File this lot away for when you have to debug a computer that's full of viruses.
First up, download and install CCleaner and run it so that you are not doing scans on thousands of junk files. Here's the link - CCleaner
Here are the links for the virus scanners. You may need them all.
ESET Online Antivirus Scanner
Microsoft Security Scanner
TrendMicro HouseCall Free online virus scan
Also make sure that Windows Updates are up to date
Now go read my post on setting up a computer with free security programs.
Checked April 2014 for link and relevance. Still very valid for Windows XP and Windows 7
This is my site for links to Genuine Free Stuff as well as some useful advice. I use most of these programs regularly. It's good gear. It's all worth having.
** April 2014. Major revamp and update for relevance happening, especially now that support for Windows XP has ended, and now that we all are addicted to our Android phones. A lot of old stuff is going.
This post in particular started this whole website...
I have been building and using computers since about the Ice Age, from DOS 3 through to Windows 7.
I have been mucking about with mobile phones for quite some time, using Symbian S60 and then Android.
Press F8 at boot to start in safe mode - Windows XP and 7
To see the details of you computer, download, install and run 'Speccy' - shows Operating System, Firewall, Anti-virus and hardware.
If you think you have a virus, start here 'Free Online Virus Scan'. Try any or all, and be patient.