HP Scanjet

I recently tried, without success, to install HP scanjet
3300 on my computer. I had converted my puter from Win
98 to XP, went on the Internet to install updated drivers
with no success at that either. Now I continually get a
pop-up box on my puter that says "This program updaes
your HP Scanning Software. You may see a message
about 'Digital Signature not found' etc. When I click OK
nothing happens except it goes away. It just pops on the
screen at start-up and at random usually when looking for
info or installing a program.

My question is how do I get rid of it? I cannot find it
anywhere on my puter

Any help will be appreciated!