I've been reading all the various solutions for this problem. I have a 64 bit processor for the XP computer.

This answer REALLY impressed me.
-----------------------------------------------
Start your computer in safe mode, and then register the Msiexec.exe file. To do this, follow these steps:
Click Start, and then click Turn off computer or Shut Down.
Select the Restart option, and then click OK, or click Restart.
Press F8 before the Windows splash screen appears.
On the Windows Advanced Option menu, use the arrow keys to select the Safe Mode option, and then press ENTER.
If you use a dual-boot or multiple-boot computer, select the appropriate operating system from the list that is displayed, and then press ENTER.
Log on to the computer.
Click Start, click Run, type msiexec /regserver in the Open text box, and then click OK.

Note For 64-bit operating systems, you also have to reregister the 64-bit MSI installer. To do this, click Start, click Run, type %windir%\Syswow64\Msiexec /regserver in the Open text box, and then click OK.

On 64-bit editions of the Windows operating system, 32-bit binaries are located in %systemroot%\SysWow64 folder. The 64-bit binaries are located in the %systemroot%\System32 folder.
Click Start, and then click Turn off computer or Shut Down.

------------------------------------------------------------------------

I was really getting excited because I actually understood the whole safe mode thing. Then it started to say you have to re-register the 64 bit msi installer, etc. etc. then I burst out laughing and said out loud.

Seriously????

lol

I'll get there

lol