there are a couple of ways of doing this task.
first is to put the hdd into another PC as a second hdd. then get the first hdd OS (the normal OS) to copy the required files onto the first hdd or onto a cd.
second method, is to dl a copy of knoppix linux cd (free). run this linux OS on a disc, it doesnt effect the hdd in any way. it doesnt install itself. you just run it from the cd drive. you can then copy all files from a hdd onto a cd/dvd or flash drive.
assuming the pc can recognise the usb device? check your bios?
ps. i recommend everyone to get a copy of knoppix. it will save your bacon one day.