Windows XP Professional OS is corrupt and damaged.

Used my Genuine Windows XP Professional spk2 cd to re-install and repair my OS on my hp Compaq d220 MT. I can browse the internet on Google Chrome only. Internet Explorer opens up to the home page but after about 15 secs gives me an error report and 'end program' window. Another words I cannot use Internet Explorer nor can I uninstall it. Have tried several times.I can sometimes download things but more often than not the install will stop right before it is complete. Don't know why??? When I try to recieve updates i get this error message "The requested look-up key was not found in any active activation context" Please help I am a beginner computer user and have no clue how to fix this problem.

Tech Support Guy System Info Utility version 1.0.0.2
OS Version: Microsoft Windows XP Professional, Service Pack 2, 32 bit
Processor: Intel(R) Celeron(R) CPU 2.40GHz, x86 Family 15 Model 2 Stepping 9
Processor Count: 1
RAM: 503 Mb
Graphics Card: Intel(R) 82845G/GL/GE/PE/GV Graphics Controller, 64 Mb
Hard Drives: C: Total - 152617 MB, Free - 146684 MB;
Motherboard: Lite-On Tech., 0888h
Antivirus: Norton AntiVirus Online, Updated: Yes, On-Demand Scanner: Enabled