How much RAM does it have? Many HP Pavilion PCs were sold with an inadequate amount of RAM installed, and you may simply need to add another RAM module to get it more responsive.

256Mb should be considered the bare minimum necessary to run Windows XP well, and 512Mb is really an ideal amount to have for most purposes.

Also, what processor is installed in your PC?

it's got 256mb but it was working just fine then one day it just slowed down. It takes about an half hour to 45 mins. just to get to booted up to the desktop.

Is it a stand-alone PC or is it connected to a network?

stand alone

Start off by making sure that all Windows updates are installed. As a bare minimum, ensure that Service Pack 1 is installed, because that contains 'fixes' for some common startup/shutdown problems.

Then follow the advice and tools suggested in the 'Helping yourself..." sticky in our 'Security' forum section, in case you've picked up any unwanted intruders that are making life difficult for you. Let us know if your problem persists after that please.

thanks for the help