computer crashed while reinstalling windows xp?

computer crashed while reinstalling windows xp.we lost a lot of files.I finally download service pack 2 from the internet.Internet still works even though pc is screwed.Right now the problem is finishing the download.A messgae tells me download cant continue because im missing update.inf also know as cryptographic service.I know where to go but when i go to administration tools.I checked on my sons pc and he has all the folders but mine are all gone.as soonn as i get cryptographic service im back in business but right now im stuck.another option was to go to system restore but that wont even work.Any ideas please help...thx