So I heard about this trick to speed up start-up...

I wanted to check with you guys and make sure this tweak is safe to use. Instead of explaining it myself, here's the section of the article where I got this idea:

http://www.winvistaclub.com/t1.html said:

One of my favorite programs for XP was freeware DriverHeavens TuneXP 1.5, which had several uncommon tweaks. One rather useful one was "Ultra Fast Booting-Rearrange Files". I tried it on my 32 bit Vista Ultimate and was pleasantly surprised to see that it worked smoothly ! Download it from the link given and install it. It will ask you to confirm on which disk your Windows is installed. Please do so. Then from the 'Memory & File Systems' tab, at the bottom you will see 'Ultra Fast Booting-Rearrange Files'. Click on it. You will get a windows, where you can see the progress. On its completion, a black windows will pop up. This process could well take upto 5 mins, so please be patient. Beneath this window, you will see a new small window asking you to, not re-start till the process is over'. Click OK and Wait ! Rather than twiddling your thumb, open your Task Manager. You will see 2 of its processes: defrag.exe and dfrgntfs.exe. On completion of the job, a summary will appear in the black window; now you may close the black windows, and the 2 processes will disappear too. Re-start. I personally found a marked change in my boot time. By the way, I have not tried the other tweaks of TuneXP on Vista.

So, my question to everyone is, would this work in Windows 7 without messing anything up?

I've never heard of that trick, and I find that on decent hardware that Windows 7 already boots super fast. So, I personally do not think that I would bother.

Windows already does this on its own. It has done it since Windows XP. Optimizing its boot up every single time.
It requires no intervention from the user.