Try a repair install as follows:
NOTE, while a repair install should leave your data files intact, if
something goes wrong during the repair install, you may be forced to start
over and do a clean install of XP. If you don't have your data backed up,
you would lose your data should that eventuality occur.
Boot from the CD. If your system is set to be able to boot from the CD, it
should detect the disk and give a brief message, during the boot up, if you
wish to boot from the CD press any key.
Once you have pressed a key, setup should begin. You will see a reference
asking if you need to load special drivers and another notice that if you
wish to begin the ASR (Automatic Recovery Console) depress F2. Just let
setup run past all of that. It will continue to load files and drivers.
Then it will bring you to a screen. Eventually, you will come to a screen
with the option to (1) setup Windows or (2) Repair Windows Installation
using the Recovery console.
The first option, to setup Windows is the one you want and requires you to
press enter. When asked, press F8 to accept the end user agreement. Setup
will then search for previous versions of Windows. Upon finding your
version, it will ask if you wish to Repair your current installation or
install fresh. Press R, that will run a repair installation. From there
on, follow the screens.
You only need to activate again if prompted to do so and this doesn't sound
like that type of situation. A format and reinstall triggers the need for
activation but the procedure is the same as the original install as is
always the case. If enough hardware changes, mouse and keyboard don't
qualify as triggers, that can require a phone call but you are prompted for
it and given the number to call if it's necessary.
That said, since the mouse and keyboard installation occurred just prior to
the issue, I'd go back to the previous mouse and keyboard for the repair
install. If you are then able to boot into Windows, place the XP CD in the
drive, when the setup screen appears, select "Check System Compatibility,"
the report it generates will point to any hardware or software issues that
should be corrected. If it comes up clean, there may be some conflict with
new hardware or possibly the hardware drivers, you might want to visit the
device manufacturer's website to look for updated drivers and to check on
issues of this type and compatibility with XP. You may have to call tech
support.
Also, as a precaution, you might want to run a virus scan, be sure the
antivirus software has the latest updates before running the scan.
