Anti SPAM Software

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.
SFC Command

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;
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;

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.
    Outlook 2003
    Outlook 2007

            .exe        (to specify multiple file types, use the following format: .exe;.com)
Disabling the Windows Genuine Advantage nag

You only get this message when XP was installed with an already used Product Key.

As a quick fix, try the following;
    Method 1
    Restart XP in Safe Mode
    Delete wgatray.exe & wgalogon.dll from c:\windows\system32  (if the DLL file won't delete, rename it to wgalogon.dll.old)
    Delete wgatray.exe & wgalogon.dll from c:\windows\system32\dllcache
    Launch Regedit
    Browse to the following location:
    HKLM\software\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify
    Delete the folder ‘wgalogon’ and all its contents

    Method 2
    Launch Regedit
    Browse to the following location:
    On the right panel, modify the value of NoRemove to 0
    Exit Regedit
    Re-launch the Add/Remove Program, and Windows Genuine Advantage Notifications (KB905474) is now removable.
XCOPY for backups

Firstly, you need to create a new Text file.

Now if you double click the desktop icon it will do what is listed in the file. With a bit of experience, you can also include the Email folder and anything else you want.

Backup file Example
  @echo off
  echo Starting...
  xcopy "c:\docs\*.*"  "h:\backup\my docs\" /d/y/c/h/r/s/k
CD drive vanished

If for no reason you suddenly have your CD units vanish and when trying to reinstall you get the following message;
    Windows cannot load the device driver for this hardware. The driver may be corrupted or missing. (Code 39)

Try the SFC /scannow command first from DOS mode.
If that doesn't work,

When you restart the CD drive should be available - if not a repair install of XP is needed.

Click Start, Run and type in MSCONFIG and click OK.
On the box that appears, click the Startup tab at the top.
Listed here are all the programs that get started each time your computer boots.
Un-tick any programs that you don't want/need or that look suspicious.  Of course the catch-22 is you may not know what ones you don't want or know the ones that look normal.

Select a Problem to see the resolution
Data recovery from a faulty hard drive

Start a Command Prompt with Admin rights
Turn off automount: mountvol.exe /n
Connect faulty disk
Run diskpart
    Enter list volume
    Enter select volume n  (N is the volume number)
    Enter att vol set readonly
    Enter detail vol to check read-only bit
Turn on automount: mountvol.exe /e