|Never play with ram like that.|
Go to big name ram sites to identify the correct ram for each system. For the most part you can't force the wrong part in.
Well, you can't ever.
Use esd straps too.
Better leave your Dad's computer alone.
"Best Practices", Event viewer, host file, perfmon, antivirus, anti-spyware, Live CD's, backups, are in my top 10