Studio 17 & Dell PC Tune

I had purchased a Studio 1735 back in Aug of 08, Received it and when I ran the PC tune up for the and it found two hard drive errors among other things. I let it fix and then ran a quick scan..all was good (Or so I thought). I then decided to run the deep scan again and there the two hard errors were again. This was the first time I turned on the laptop. Cause for concerns, now I had an exchange done as the laptop was plagued with problems. I get the exchange months later and ran the Dell PC Tune and wham hard drive errors akong with a few other issues. I unistalled and then tried to reinstall it and could not find it so I download the automated pc tune from Dell.com and ran that no problems found. I call the tech support to see if they could help me find the original software that I had bought and paid for at the time of the build. I was told by the untrained tech (Trying to be nice as I have alot of other names for those I have to deal with) told sorry you have a trial version. Mind you that the exchange was to have mirrored my original system. So I ended e-chat as I could not take dealing with them anymore. I then looked around within the laptop Vista 32 bit and found and reinstalled it. Ran it again no problems at first but when running it again it found hard drive errors and other problems. So with all that being said and the fact when I asked a rep on the phone if it could be a software error they said yes but wanted to replace the hard drives and MOBO had me wondering was it the laptop or the software. So my question is could it be possibly the Dell PC Tune or the another case of bad hard drives, these was found in two different laptops running brand new software?  Why would the online version on the Dell site not see any issue but the one that was preinstalled did. I also ran the diag within the laptop and it did not see any issues either but the tech rep insisted on hard drives and mobo. Is there a way to get or download a different Dell PC Tune to see of that is the issue and it not be a trial as I have already paid for it? Or is it possible that it really is the hard drive..which with all that I have been through with Dell in the last 5 months would not surpise me to be both as the system was built overseas in Malaysia.