Some services not working and dll. files missing

[Ian]

Windows XP Home, nominally SP3, but installation faulty.
Some services not working and dll. files missing.

(e.g.i) Browsers work but START > CONNECT TO > (Empty)
could not start network connection Error 126, missing Msinfo 32.dll
e.g.ii) Printer that was previously installed and working fine is now not
in Printers and Faxes,
and reinstallation is rejected, with error "The print spooler service is not
running".

I need some sort of general analysis, (to see how bad things really are) and
then a method for repair, (missing file replacement and restarting services),
but I am not an expert.

Is it helpful/possible to uninstall SP 3 and SP 2 and then download and
install them again?
Would this supply the missing files and restart services.
Should I consider a reinstallation of the XP OS? Have reinstallation CD and
product key but have never done this before and nervous of crash/ getting
stuck in some loop or losing all installed programs.

If reinstallation needed please warn me of risks and suggest detailed guide
to walk me through it.

Grateful for your advice.
Regards - Ian

 

[David B.]

Have you tried a system restore back to a point when things were working
properly?

 

[Ian]

Thanks for replying.
The restore capability was disabled when several "services" failed, but
after sfc scannow in "safe" some files were copied back from somewhere; and
after emerging from "safe" I found that "restore could be switched on again.
Unfortunately no suitable restore point early enough is available.

Is there some sort of scan that can list missing files or failing
services/processes ?

Regards - Ian