A 100 Toshiba won't start

I recommend reinstalling Vista, and replacing the Hard Drive as well. The errors being sporadic could be indicative of a hardware failure or a software failure and could be both in tandem.

First - re-seat the harddisk and reboot the computer. If the computer does not boot up then reboot andgo into the BIOS configuration to see if the BIOS detects the hard drive. If itdoesn't detect the hard drive then it could be faulty.Then the hard drive needsto be replaced in the computer/laptop, Windows installed and the computer orlaptop's device drivers plus your programs etc. to get a functioningcomputer/laptop again.

The reason why Windows XP installation CD cannot detect the hard drive is because your Toshiba has a SATA hard drive and the Windows installation CD does not have the SATA driver on the CD.
If you do not have the SATA driver then you can get around this problem. Please click on this link and follow my instructions :-
http://www.fixya.com/support/r4335035-installing_windows_xp_sata_hard_drive

Yes it does matter. XP was configured for the old Toshiba and this will only work if both Toshiba laptops are exactly the same model.
To get your new Toshiba operating, put the new hard drive with the Vista operating system back in the Toshiba laptop.
To transfer your data from the old hard drive, purchase a USB adapter hard drive case and place the old hard drive inside this case. This will then be an external USB hard drive.
Plug this USB hard drive into the new Toshiba's USB port and it will detect it as an external storage/hard drive. You can then open the various folders and files and copy the data files to your new Toshiba.
To free up disk space on this USB hard drive, delete the Windows folder, Program Files folder and other folders that are no longer needed.
Use this hard drive as a backup hard drive etc.

the western digital website, under support/downloads is the best place to start. Unplug the device and install the software, reboot and then connect it.

You can boot from original Windows disk but make sure you choose to repair installation. This will replace all the windows files but will not touch any of your personal data, programs or drivers installed. After youve done this repair install you should be able to start windows and get yourself an external hard drive and back up all data. Maybe then do a complete format and reload operating system to get your laptop running like brand new again. I dont know why your IT specialist has never tried this? Hope this all works fine for you ....... cheers from Scott

You've probably got to have your computer configured to boot from a rescue CD before it can recognize and install the new harddrive. Also make sure that there is an operating system installed on the hard drive . If not it will not do anything until you install one. This will be automatic if you install a new XP or Vista DVD into the computer's DVD drive the reboot.

Has this just recently started happening? if so you could try a system restore to your latest stable operating point.. vista is sometimes known to crash after power settings are changed... you could also try reverting your power settings to their defaults( start / control panel / power )if this dose not work it sounds very much like a hardware problem. firstly i would take your power cord to a local repairer to have it tested to make sure it is putting out the correct voltage and mA.. if your transformer is ok you need to test if your problem is with your hardware or software on the pc.. I would install vista on a separate partition and see if you have the same problem. if your new install of vista works fine when plugged in you should back up your needed files format your hard drive and do a complete new install of vista. but if your new install of vista (on the separate partition)crashes in the same way your trusty old laptop will need repair or ebaying

Does still have warranty? Try and talk to the retailer if there is a warranty. there should be at least 1 yr of it.

This is almost always a failed hard drive, however, it can sometimes be a corrupt operating system. Start by trying to reformat the hard drive and install a new operating system. If the hard drive won't format, or if you have any issues during or after the install, then the hard drive has failed and will need replaced.