Had the same issue with a satellite also,tried everything you did, even tried re-installing windows 7 got but only get an error during the installation phase..Just a heads up, This is one problem that occurs with Toshiba laptops over time.Not sure of the cause but it happen to my Toshiba satellite p205-s6237,then i just re installed widows XP on it and everything worked fine after that.
If you have important information on the hard drive i recommend making a back up by; taking out the hard drive and connecting it externally and save what you need,then format the drive and get a XP cd and install it.