Dell Inspiron 9400 laptops need reinstallation, no boot disks, Dell sent disks but I don't know what to do with them

We have a bunch of Dell Inspiron 9400 laptops which were purchased new and sent out for use in a conference.  A bunch of them came back all screwed up, apparently the people using them tried to install something on them that messed with the operating systems and then absconded with all the original disks.  Now, when we try to boot the computers they give us this message: "The Dell system recovery tool has detected an unsupported change in your master boot record.  The tool cannot run at this time."

We've spent literally hours waiting in Dell's tech support queue, and then waiting for people to call us back.  Finally we got a bunch of disks with titles like "Drivers and utilities - For reinstalling Dell Inspiron and XPS System Software".  None of these disks, when inserted into the DVD drive, causes the computer to boot.  None of the disks say "bootable" on them.  I'm ready to tear my hair out at the thought of more hours spent waiting for Dell to get around to talking to me again...can anybody PLEASE tell me what I'm supposed to do with these ferslugging disks to get the computers running again?