Thanks for your help.
With my old hard drive installed, I started the pc and got the following message:
Windows could not start because the following file is missing or corrupt. windows root/system32/hal.dll
I looked this up on the internet and tried everything suggested without any luck and also did all that was suggested by yourselves, so I have now removed this hard drive and replaced with new one. Upon startup, I deleted the partition, (as I had used it previously) created a new one and installed a fresh version of windows.
After updating windows from windows update, I will load just a couple of programmes that I use regularly for work and see how it goes. If situation arises again, I will post on here.
Thanks
Rob