Thank you both for your replies. I understand that the response from chkdsk may appear to point towards a hardware issue, but I do not think this is the case for three reasons:
1) Apart from the response I described above, it also indicated that there was 0kb in bad sectors, and seemed to report 'successfully' for each stage of the process.
2) The boot problems happened very soon after I made changes to the system in an effort to speed it up (e.g. stopping a number of windows services, using a 'registry cleaner').
3) I can access files from the offending drive C:\ from my Ubuntu operating system (this one is able to boot) in a different partition.
For these reasons, I suspect the problem is to do with specific system files e.g. the non-installation of a specific update, or a corruption of the registry.
I am reluctant to carry out a system reset unless it is an absolute last resort. I am very grateful for your help and wondered as one last request whether you could point me towards any alternative places on the web or indeed this forum that might have some more experience with these kinds of issues.
As one last piece of information, I should also probably mention that there was one course of action which did result in different behaviour from the BSOD - this was when I replaced the files in my c:\windows\config directory with the files in the c:\windows\config\RegBackup directory. This resulted instead in a black screen which seemed to occassionally flash up with a window for a split second every so often.
