I installed the BricoPack Vista Inspirat Ultimate 2 out of curiosity, but after i installed it, my computer slowed down epically, and the task bar looked like Windows 98. So I decided to try system restore, and that failed. My next best bet is to uninstall it, which didn't do anything. Now I'm stuck with Windows Classic and a pretty slow computer compared to before. Any way I can fix this?  
btw I have xp professional service pack 3

Well 455898334 The bricopacks does not slow your computer since they're merely shell extensions which replace your system files But some additional 3rd party software comes with it like 'Y'z shadow' may cause your computer to slow dow due to usage of RAM
If you've uninstalled your bricopack, there won't be any remnants bt due to your running programs it may vary.
So if you want to see what bricopack really does, re-install it in Safe Mode (press f8 at startup) & deselect installation of Y'z Shadow
 
Btw, when did you defragment your PC last?

never...

Well If you haven't defragment your Pc atleast within 3 months after windows installation, it's not so surprising to have it slow
I cannot say it's a cause of bricopack unless due to y'z shadow

I just reinstalled it in safe mode, but the theme is still Windows Classic, and whenever i try to change it, I get the error:
The visual style could not be loaded because the file failed to load.
Details:
                      lOKl

Try this: http://www.softpedia.com/get/Syste [...] -SP3.shtml

Where should i put that?

never mind, i got it
Thank you.

No problem, enjoy