Personally I'm not a big fan of it. You spend too much time either teaching it what is right and wrong, or too much time going through the SPAM or Junk folders.
They basically work on two principals. They have a list of known sites or people that send spam or they look for key words within the email subject or body.
For example, a key word may be PORN. If I sent someone an email with the phrase "Watch out for porn site scammers" then that email may be blocked if the receiver has anti-spam software. But these programs can be fooled. Instead of PORN, I could write it as P_O_R_N which may not trigger the anti-spam software.
I'd rather get email I didn't want than not get email I did want.
All the good anti-virus programs, AVG Free Edition included, now have built-in spam detection.
The System File Checker is a useful tool to check the integrity of your system. It can be used to extract a file that needs replacing or has become corrupted or to recover system files. It is a good starting point in trying to fix a PC that would otherwise need to have the Operating System reinstalled.
To use it, type SFC from the command prompt.
Can't access Secure Web sites
If you have trouble trying to access sites that are secure, that is, start with https:// and are getting the message 'This page cannot be displayed' then try the following;
Make sure you have anti-Spyware and Adware, they are updated and perform a full system scan.
Delete Temporary Internet Files and Cookies. Go to Internet Explorer and navigate to Tools, Internet Options and click Delete. (This is for those not running IE8, the same is still possible under other versions, you just have to look a little harder)
Delete the file INDEX.DAT. This file is usually left behind after performing the above step. You will need to reboot in Safe Mode to delete it as it is a system file and is 'locked' by Windows normally.
You also need to delete your User Profile. Log on as Administrator in Safe Mode. It is located in Control Panel, System, Advanced. Select Settings in the User Profile section and click Delete. You will loose you personal customisation settings but no data. When you reboot in normal mode you will have to re-setup your Desktop etc.
Another work-around is to install another Web Browser. Firefox is free, looks very similar to Internet Explorer and provides a quick solution.
Duplicate Incoming Emails
This problem seems to stem from a file corruption in an Outlook Express file called POP3UIDL.DBX. The solution should be as easy as deleting this file. It will be recreated the next time you click Send/Receive. Of course, make sure that you aren't really getting someone sending you the same email twice. This may be happening without their knowledge due to a virus infection on their computer.
Removing Viruses from System Volume Information Folder
If a virus gets into the folder where Windows keeps the information for System Restore points, your anti-virus program may not be able to access it. To clean out all the saved restore points do this;
click Start, Control Panel, System, System Restore and tick the box to turn off System Restore on all drives
reboot the PC
go back to the System Restore settings and un-tick the box to turn System Restore back on
reboot the PC
The System Volume Information folder will now be empty and all viruses removed.
Outlook blocking attachments
If you receive the following message:
Outlook blocked access to the following potentially unsafe attachments...
Quit Outlook, click Start, click Run, type regedit and click OK.
Verify that the following registry key for your version of Outlook exists. If it doesn't, create it.