Hi denvalley. Welcome to Geeks to Go!
Let's work on the rebooting problem first. It could be the result of a couple of things, including incorrectly installed hardware (modem, lan card, etc), a bad boot sector, and possibly bad RAM.
So, have you installed any hardware or adjusted any hardware on your system recently? If so, please take it out and reinstall it.
Are you getting any Blue Screens and/or other error codes? If so, please try to write down as much of the errors as you can, as the actual codes and file names they might display will be helpful in tracking down the problem.1. Test the RAM
Testing the memory is an overnight thing, check it in the morning and stop the tests, if there are memory errors, (which would cause installation problems), they would show in red.Click this for a guide to using MemtestClick this to download Memtest
Run it overnight if possible2. Run CHKDSK
Put the Windows XP CD
in the cd-rom drive and shut the machine OFF. Power the machine back on and watch the screen for the prompt "Press any key to boot from cd"...press the spacebar once.
This should take you to a "Welcome to Setup" screen...Press R to load Recovery Console"
On the next screen, select your operating system by typing the number to the left of it. In most cases, this will be 1. C:\WINDOWS...so type 1.
If you are prompted to type a password, leave it blank and press "Enter".
This should take you to a command prompt...C:\WINDOWS>
Type chkdsk /r and press "Enter". Note the space before /r. You may be told the volume is in use and asked if you want to schedule this to run on the next boot...type Y and press "Enter". This should start the chkdsk operation.
If the machine doesn't reboot automatically, but returns to command prompt, type exit and press "Enter". The machine should reboot...do not press a key to boot to cd...let it boot to the HDD.
This will be a very long check and may appear to start over a few times...this is normal, let it finish. 60 to 90 minutes for this check is not unusual. It should then automatically boot to Windows.3. Run SFC (System File Checker)
It can fix certain issues in Windows where specific system files get corrupted, deleted, or infected. Basically the System File Protection watches the system files and checks their integrity against it's knowledge of what these files are supposed to look like. Generally if a system file get's "messed with" windows will let you know and give you the option to dissallow the change, sometimes you don't get this option though. The System File Checker is a command line utility that will initiate a scan of all the system files to make sure they are in their original state, present on the system, and or working properly. It's an easy tool to use but the user HAS to have an XP disk for it to work.
Do you have a valid XP cd?
If so, place it in your CD ROM drive and follow the instructions belowStart > Run > cmd
then typesfc /scannow (note the space)
Allow this to run until you get a message saying it is complete.SFC
- system file checker, retrieves the correct version of the file from %Systemroot%\System32\Dllcache or the Windows installation source files, and then replaces the incorrect file.
If you want to see what was replaced, right click My Computer > manage, expand event viewer > system.
I also highly recommend you take a full system backup, in case we need to reinstall Windows.