O_O
First time using a computing system?
One obvious answer would be to first, backup critical data, and then do a full reformat/reinstallation.
You use Acer, they would have given you recovery disc. You these (by restarting computer and inserting disc just before it pops the 'loading Windows' screen). It will guide through a setup, reformat and reinstall Windows as per new condition when you just bought it.
Do note, performance may not be similar to that when new. At times, these manufacturer misses out driver software in the recovery discs, so when you see lots of error messages upon complete of reinstalation, get to the Internet and run Windows Update. For some like me, we opened the casing and clean it from dusts.
Be sure to maintain performance, get reliable Firewall and AntiVirus, as well as AntiSpyware software, with registry maintainer software.
Recommended:
AntiVirus: AVG Free 8, Threat Fire
AntiSpyware: Lavasoft Ad-aware
Registry Maintainer: Advanced WindowsCare Personal