If hitting ctrl-alt-delete doesn't bring up task manager and you have no
reset button, then your only choice is what has been already listed in this
thread.
That said, if this is a new system as you state, it should not be constantly
freezing. Contact HP, you are still under warranty. No new system should
be doing this unless you've installed applications in which case it could be
some of the applications you've installed. Depending upon the applications,
they may not be compatible with XP and as such might be the cause of this
issue.
You need to find out the source of the issue if this didn't happen before
you installed any of your previous peripherals or software.
First, be sure your antivirus software has the latest definitions and run a
virus scan.
Also, download, install and run Ad Aware:
www.lavasoftusa.com
Don't assume you have neither of the above just because the system is new.
If you connected to the Internet without a firewall, you could become
infected.
If your system is clear of viruses and any malware, open Control Panel, open
System, go to
the Advanced tab, click Settings under Startup and Recovery, remove the
check from "Automatically Restart" under System Failure. This will cause
the system to blue screen instead of restarting on errors and the
information on the blue screen may give a clue as to the source of the
issue.
Open Control Panel, open Administrative Tools, open Event Viewer, look for
errors corresponding to the crash, double click the error, the information
contained within may give a clue as to the
source of the problem.
Assuming you have an XP CD and not a recovery CD, place the XP CD in the
drive, when the setup screen appears, select "Check System Compatibility,"
the report it generates may point to problem hardware or software on your
system. If you do not have an XP CD, you can download this application
known as the Upgrade Advisor from the following site:
http://www.microsoft.com/windowsxp/pro/howtobuy/upgrading/advisor.asp
Note: If you have access to a broadband connection it might be best to
download using that as this is a rather large download.
Check for the latest drivers for your hardware, especially your graphics
card and soundcard and all peripherals connected to your system. No not use
Windows Update for this, go to the device manufacturer's web sites and if
you install updated drivers, ignore the message about drivers being unsigned
by Microsoft. *Again, just because the system is new, don't assume all the
drivers are up to date. Drivers change frequently, you have no idea how
long the hardware was sitting on the shelf before sold, you need to check
for updates at the system manufacturer's website as well as at websites for
all of your hardware manufacturers.