Try to interrupt the boot process and get into safe mode. For most boxes this requires tapping the F8 key, when the box is beginning to boot. You'll be presented with a screen asking how you want to start windows. Choose safe mode. Allow it to complete the boot. It'll look strange because your normal video drivers won't be loading and it may take longer to boot but that's fine, it's supposed to look that way. When the box is booted, try a restart.If no file was corrupted, you should have just finnished that update that was giving you trouble. If you're back to square one again, with the same sequence you saw at first, you've got a couple options. 1/Hit F8 again before boot and try "last known good configuration that worked". It may roll the update back for you. 2/Hit F8 and choose safe mode, let the box boot and go into control panel, add/ remove programs and after the list has populated, look down it to microsoft software updates. Remove the update that is giving you an issue. It may simply have been a driver incompatibility issue. If you're not sure which update it was on the list, look at the dates of the installs. You may have to remove all of the updates you did that day and re install each, one at a time, to find which one to avoid by trial and error. 3/ Use your xp's ( I assume this is xp) system restore function. If the update managed to create a restore point before it died this can also do the trick. Got to Start / help and support / pick a task / undo changes. Create a restore point, just in case and name it something you'll remember as giving you an issue. Then choose a date just prior to the update that gave you the issue. It'll roll back any drivers etc., to that date. Sorry, that's all I can think of off hand, without knowing more info. Edit: Ok, you're sure that you gave it the chance to boot in safe mode. Sometimes it'll hang when loading mup.sys and looks like it's crashed but is still running. If you left it for 5 minutes, we could be sure. Failing that, there are a few options. 1/ The use of recovery discs that may have been included with a store bought PC like Hp or Dell. You'll get to keep your data, but may have to re install some apps. 2/ Make your own boot disk if you have access to a pc (obviously you do, you're here) Here's a site that will guide you through the process. http://www.windowsnetworking.com/articles_tutorials/Building-Using-Windows-XP-Boot-Disk.html 3/ The use of a program called The Ultimate Boot Disk for windows. It's free and you can download it here http://www.ubcd4win.com/howto.htm . It WILL get your box booted in a basic mode that you can use the built in utilities to fix the issue. You'll need to do a download of about 130 megs, have a blank disc and have your XP disk and your service pack #2 disc(preferably) to go this route. Being somewhat computer savvy will be a definite plus here. 4/ Use XP's own recovery tools. Insert your XP disc in the drive and boot. Choose recovery when prompted. Hopefully you have the bios set to booting the cd rom drive, if not, change it to that in the bios settings screen. All bios's are different, so I can't tell you what tab it will be under, just that by hitting the "del" key when booting will get you there. Don't change any other setting. I've had mixed results using the xp recovery tools from, it worked, to it failed miserably. Use it at your own risk. 5/ If you have a second hard drive kicking around that's good and not being used because it was smaller or something, you could always install XP on it, make it master and use it to grab the files you need off of the old drive. Partition and format the old drive,make it master again, reinstall XP and then grab those needed files off the now slave, after you've re installed the software needed to use them. This is gonna be your last ditch route, because of the time and hassle, but at least you won't be losing anything you need. Now I'm tapped out for ideas. I have had exactly what's happened to you, happened to me. The list I knocked together here for you, is the order I would try things. Remember that the XP rescue utility aint all that good. You're on your own there.

Thanks for info Will update you with which suggestion worked best

Have to abandon ship/question on this topic as when put hard drive in caddy to copy over files error message 'Disk not formatted. Format now?' So now onto another question on how do I get data from a corrupt/damaged hard drive? Got any suggestions?

Try starting with operating system disk. If it's Windows XP, put disk in driver first. It will make it try to reinstall windows alltogether and usually interupts the glitch.

Do you have recovery discs for your PC? Try running them, might solve your problem.