New computer, crashed, not such what topic to put this in

I purchased a refurbished computer for X-mas. Recently it had been freezing up about every 5 minutes, I have internal and external virus protection, spyware etc. My "other" tried doing disk defrag, virus scans, but they froze up. I tried to use a restore point, but all the restore points were gone even though we set them up.

Last attempt to run virus scan froze, so my "other" just shut down the computer (we use window vista). When I started it up it indicated recent software/hardward changes (he unplugged the external USB when the computer was off, thought that was the problem) so I started normally and the blue screen came up and said the computer was shut down to protect. I restarted again and I then got this message " disk boot error" please install disk and restart (we did not get disk with the computer, so not an option). I restarted again and got the option to start normal or go through repair/fix, I started under repair/fix to see if this would help, I then go the following message "Windows is having trouble communicating with a devise connected to your computer. This can sometimes occurr by unplugging a removable storage devise such as USB drive while in use or by faulty hardwar such as a dard drive or CD-ROM drive that is failing." The error code said: An unexpected I/O error has occurred. ***So bring us to the present, now when we turn the computer on it says "BootMngr is missing, press ctrl alt delete".

We are dead in the water. My question is, could this be a bad hard drive or CD-ROM, it was a referb and we have a warrenty.. or is this a sign of a possible virus, it does not seem that way, but you never know? We plugged back in the USB external storage, but that did not work and now we just have a missing boot manager... help if any one know what direction to go: O, I can get into boot menu and set up, but it does not take f8 for safe mode and I can not get into recovery f11?