Deleted xp services

I had a virus problem , and that probably deleted keys and values associated with several xp services.
Will a repair install (in-place upgrade) of xp reinstall these services ?
Or i need to reinstall XP (with format) , or maybe install sp2 ( i use sp1 ) ?

Thanks.
Luiz.

 

That´s the problem , i´m not 100% sure if it´s malware free.
I´ve been to a forum with HijackThis Log Help , and the last instruction was ( as i have many critical files that failed signature verification ) to install sp2 and post a new ComboFix log . This after have sent these logs in sequence as follows:

- Deckards System Scanner
- ComboFix
- Dr.Web CureIt

Nothing found.
I think that the best would be do a repair install before sp2.
But, doing so, i´m going to activate several system services that are now dead, this in a system without any security patches after sp1.
Between the repair and sp2 , i must do a bios update. Maybe do an ASR backup, and install updated drivers for the Audigy 2 , modem , graphic adapter. Don´t know if is safe to do these before repair, couse now in every simple install the system seems to freeze for more or less five minutes.

Any suggestions ?

Thanks
Luiz.