Vostro Series - Any known issues?

We purchased a few Vostros for business purpose. I have noticed 2 OS failures within 2 weeks. There appears to be something not working right on them. For the first one, I had to wipe out the hard drive and try partitioning again, however even that was not happening so I started suspecting hardware issue. Finally ran a lot of Dell diagnostic tools and followed a series of steps of steps to debug the hard drive post which the OS installed. Today I see another laptop behaving in the same way and this is becoming painful as business keeps getting affected everytime a production laptop goes down. I definitely do not want to waste my IT resources in restoring OS for all laptops from the scratch. I have 3500 and 1015 series Vostros. Is anyone else facing a similar issues?