If you upgrade you existing OS to Windows XP, it will void the manufacturers warranty. I found this up today when I called on technical support for the monitor on my new HP(which lasted 3 months). They told me that my computer was no longer warranteed, but because my monitor did not work when I attached it to another computer that they would honor the warranty this time. This also applies if you upgrade with the HP XP upgrade offer, or so I was told.