Does hard drive make any unusual sounds or clinks - that it didn't before?
Have you or anyone run disk check, to check for bad sectors on HD (hard drive)?
Check your hard disk for errors in Windows 7
https://support.microsoft.com/en-us/kb/2641432
and
Resolving stop (blue screen) errors in Windows 7
Since this is a fairly new fresh install , the OS should not be messed up yet..unless the HD is an issue..and the HD is messing up the OS...
your Ram is fine