Hi there,
since yesterday everytime I boot up my computer as soon as all is loaded a box comes up on the screen which says "windows cannot find C:/windows/logon.exe" after I click it away everything works ok but I have no idea why it is doing this as to the best of my knowing i havent changed anything. Any ideas guys?

Suggest you try this...

Place the XP Windows Install CD in the CD drive.
Go to the Accessories...Command Prompt
enter: sfc /scannow
There is a space between "c" and "/".
This could take from minutes to hours to run.