Seems you may have a memory issue. Try removing any memory modules very carefully and clean them off gently with a q-tip on the very sensitive gold connectors at the bottom of the modules. After doing so blow hard or vacuum the ram slots when the memory would go into to clean them of any debris. Just be careful to first make sure you computer is PLUGGED IN but TURNED OFF when doing so and touch the case before touching anything to discharge yourself of any static electricity you may have built up. If you move around during any work make sure before touching any other sensitive parts that you ground yourself again, by touching the case once more (ex. reinstalling the memory).
Next, we need to make sure your HDD isnt corrupted with any bad sectors and put in windows xp same version CD (ex. xp home edition sp3) and boot from the cd then:
1.When the "Welcome to Setup" screen appears, press R to start the Recovery Console.
2.If you have a dual-boot or multiple-boot computer, select the installation that you must access from the Recovery Console.
3.When you are prompted, type the Administrator password. If the administrator password is blank, just press ENTER.
4.At the command prompt, type chkdsk /r , and then press ENTER.
5.At the command prompt, type exit , and then press ENTER to restart your computer.
If after doing this you will most likely still get the same error if you tried to boot into windows (try above first to rule out the ram error), you will need to do a windows repair. You will need the same windows xp version you are running...for instance you said xp home, need to know the sp version such as sp3. Once you aquired the disc, ll you need to do is boot from it, and go through the steps until you reach the option to repair the windows build...its not the first set of options...its past pressing f8 to continue. Just dont select format hard drive...as that's another option in the same area as repair windows.
You will most likely not lose any windows applications...but you will need to update windows again, because it repairs windows registry and files...so those will need to be downloaded and reapplied.
Let me know how it goes or if you run into a bump.
P.S. when you get it working, I highly suggest you run a check disk with fix all problems found option checked...cause your drive may have bad sectors that need to be repaired. Or easiest way is to press "windows key + r", then type "cmd" into the run window, then type "chkdsk /f c:" into the command prompt.
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