System boot failure

The operating system is Windows XP SP3 fully updated. The machine worked
perfectly yesterday but failed to boot up successfully this morning. Nothing
was changed on the machine before it was switched off yesterday.

On attempted reboots I get the screen which tells me windows did not start
successfully. I have tried all the obvious options with the following
results.

1. Let the timer run down - system freezes sometimes with a centimetre wide
white bar across the screen and sometimes not.

2. Select start windows normally - the timer stops then same as above.

3. Select start in safe mode (all three options) - starts to load drivers
then freezes always at the same place.The last driver listed on the screen
when the system freezes is:

multi(0)disk(0)rdisk(0)partition(1)WINDOWS\System3 2\Drivers\Mup.sys

Is this likely to be an operating system problem or a disk problem and does
anyone no anything I can try to get the system to boot. I do not have a
Windows CD for this machine but I do have another machine running the same
system for which I do have a CD.

Graham.