Funnily enough they're system files - which is why your systems check found them! What you do is repair/replace them. That is what the system check tool is for. Didn't you notice that option when you were running the check?
If for some reason you can't access these files from your system disk (maybe your OS came preloaded) they can be downloaded from the internet. Let me know if you need the links.
Thank you moonacre - I really am grateful for your reply.
Yes, I did see the prompt, but the System Checker was stopping every few seconds with File Changes, and when I was told to reinstall the corrupted files I was totally lost.! Being fairly new to all this I wasn't sure what to do. I did find a website with all 'Dll's' - Do I just downloaded them from this site?
Best to use the system check tool if possible as then you can be sure the files are genuine. Run the tool again. When it finds a corupt file it will ask you what you want to do. Select restore file and click OK. It will then ask you for a location. Click the browse button and point it to your Operating System CD. Follow the prompts and it will copy the file to the right location. If for some reason you can't do this then find these files on the internet. It is worth trying to find the same versions as the ones you are replacing. Find the file using windows explorer and right click. Select properties and make a note of the version number. Do the same with the downloaded file. If both the same then great. For safety, rename the original by adding .old to the file name then simply copy the new file to the same location as the original. The renaming is important because if anything goes wrong you can delete the new file and change the name back on the old one. If you can't find the same file versions then replace with newer version not older.