No, it will not delete your stuff. But be aware that you'll be making choices during this process - and if you make the wrong choice you could wipe out everything.
Particular care is required with Figure 3 - if you don't click "Repair your Computer" you could overwrite everything. So be sure to click on Repair your Computer and no other choice on that screen.
Also, the Windows Complete PC Restore can set your computer back to a time before you had installed your programs and data files - so be careful using that.
The point here is that anything that you do to your computer has the potential to corrupt stuff - so a good backup is necessary in case of a disaster. I've done several Startup Repairs at work and haven't lost any data yet - but that doesn't mean it won't ever happen.
Startup Repair is one of those things that "could" help you - but I suspect that it won't show much of a difference. It may even show that there aren't any issues that it can fix.
Which brings us to a discussion of the Windows Startup Cycle. If you instruct Windows to create a log of the boot process, you'll see that there's a bunch of stuff loading. What stuff is needed, and what stuff isn't? Well, that's a matter of breaking down the different areas of your computer to see what's starting with Windows.
Most often it's the startup items that are in the System Tray (aka the Notification Area) by the clock in the lower right corner of the screen. After that, there are other areas within Windows where programs can launch at startup, and after that, there's the services that launch at startup. Each individual entry doesn't usually take up that much of your resources when booting - but a whole bunch of them can, or a single one that's malfunctioning can.
For trimming the startups, I recommend that you use this free program: http://www.microsoft.com/technet/sysintern...s/Autoruns.mspx
And then compare the startup entries that you find with the Startup List at the top of the forums (link here: http://www.bleepingcomputer.com/startups/
) Please be aware that certain startups can be either good or bad entries depending upon their location.
Please don't just start deleting stuff - as there is a chance that it may hose your computer and you may not be able to even boot up. If you have any questions about the startups, please post back here with the name and the Image Path and we'll do our best to help you.