it happens sometimes, i have experienced similar issue couple of times
here what i was able find in net
Cryptographic Services runs under Network Service which would require Users to have read access. Provided BUILTIN\Users with read access permission to Drive C and the .Net Framework 3.5 sp1 installed successfully
second time when encountered similar issue
added the NETWORK SERVICES to the C: drive and allowed read access





by: Omego2KPosted on 2009-10-27 at 07:31:16ID: 25672803
Please post operating system and OS language.