How can I fix this?

My computer went through a phase of restarting whenever I turned it on. Now when I turn it on all it says is "the following file is missing or corrupt...You can try to repair this using the initial startup CD-ROM and selecting 'repair' ".

I don't have a startup CD-ROM. Is there any way this can be fixed? If not, is there any way I can get some important files off it that I need?

How can I fix this?virus protection

Firstly it's not possible to solve your problem without CD-ROM.

if you want to get ur important files than you will have to

1. remove your hard disk from your computer.

2. then u required to attach your hard disk someone else computer and you can get your important files from it.

How can I fix this?agv

That sounds like a pretty serious problem. You should hire some professional service for that. There is stuff I could tell you to do, however, it is fairly complex and doing it wrong could delete everything on your hard drive. If you go to someone who can be at your computer he can either fix your computer or take the hard drive out and get files off of it (depending on the situation). That would be the best course of action. Unfortunately, chances are that you are screwed.
You MAY not need the Startup disc. Most computers in the past few years have the "disc" on your hard drive (Usually under another Drive letter such as D, G, etc...