Unfortunately it will, but you can always undo the System Restore if you don't like the results. If you are using XP and want to try it -
Click Start (bottom left of screen) > Help and Support > Undo changes to your computer with System Restore (under sub heading Pick a Task) > Restore my computer to an earlier time (default) > Next > select a date you want to restore to (Bold Numbers) and >next again.
If you don't like the results follow the above steps again but instead of choosing"Restore my computer to an earlier time" select "Undo my last restoration" which will take you back to where you are now. Hope this helps.