There so many factors, that one thing could possibly help. So here are a few list:
1) Do a defrag
2) Open up command prompt, and schedule a chkdsk /r to check for any disk errors
3) Try to keep tab count to a minimum,
4) Clean up your desktop
5) Try to disable unnecessary start up programs.
Also, what are your specs? I have an Acer laptop as well, and doing these things keeps it running top notch. Then again, I take my back panel out and get the dust out twice a month.