as above really, trying to sort out my toshiba u400 laptop.

When i boot it says there being a problem casued by a recent hardware or software change, if i try to boot normally, the vista loadup bar starts, and then screen goes black, and basically something starts loading, a whole list of .dll out of 89757, but then it freezes on one :
!! 0xc01a001d !! 28415/89757 (\Registry\Machine\COMPONENTS\deriveddata...)

if i choose boot from last known good configuration it still doesnt start, and when loading in safemode it freezes on one of the items it trys to load and even if i leave it for 24 hours it still doesnt work. freezes on : Loaded: \Windows\system32\drivers\crcdisk.sys

sometimes when i turn on the moachine although i can hear it running the screen is black, and therfore i have to take out the battery and try again and hope i get the option of atleast choosing safe mode etc

I would ideally like to solve the problem without just formatting it, as although i could whip out the HD and get my data off its a sata and i wont have a sata to usb cable

i tried inserting my vista disc but even if i select repair, it tells me that it has repiared and that i must restart, only for it to turn to a black screen, and carry on loading the .dll and once again freeze at : !! 0xc01a001d !! 28415/89757 (\Registry\Machine\COMPONENTS\deriveddata...)

Did you actually make a hardware change? If not then try booting up with different part removed to see if there is actually a piece of hardware causing an issue.