Running Dell Diagnostics On-line

I have an Inspiron 518 with Windows Vista. I attempted to run a full Dell Diagnostics on-line program, which is supposed to take about 60 minutes. After almost 1 hour 45 minutes, it was still running with the same window with a message that the results will be available shortly. I shut it down assuming there was some problem. I recently had a blue screen of death which resolved itself, and problems shutting down/restarting, and the system checked discs, etc. and fixed some problems. I want to run a full check-up on my PC. Is there some other program I should use? Any suggestions would be greatly appreciated!

Thank you,

Paul