It is only a problem if you have encrypted files or folders with th XP-Internal encrypting method EFS (Encrypting File System), they lok green (if you have activated the color feature for ntfs (ntfs looks blue) and efs files)
I forgot: and your loose stored Certificates, but this has not to do with certs for cellphone.
I mean special certs that you had buyed or selfgenerated and stored in the User-Certificate Store. However I don`t know many users which ever buyed or generated a cert.
But it is the same way like efs, you loose the Cert-Store but the computer and your user account is working and you can access all the files if you never used EFS.
Otherwise you have to decide how important the files are....