A System File Check might solve the software install issues, but you will be prompted for your XP cd.
Start > Run > cmd
note the space when you type.
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.
System File Checker (sfc)
Scans and verifies the versions of all protected system files after you restart your computer.
My late husband was a Marine 1968-1971 but they say there is no such thing as an ex-Marine, just a dead one. He was one of the most polite people I have ever met, and also the fiercest. ;-)