Hello again, here are the specs of my school pc. It looks like the specs are really better than that of my laptop.
Operating System: Windows 7 Professional 32-bit (6.1, Build 7601) Service Pack 1
Language: English (Regional Setting: English)
System Manufacturer: Hewlett-Packard
System Model: HP Compaq dx7400 Microtower
BIOS: Phoenix - AwardBIOS v6.00PG
Processor: Intel® Core2 Duo CPU E8300 @ 2.83GHz (2 CPUs), ~2.8GHz
Memory: 3072MB RAM
Available OS Memory: 3062MB RAM
Page File: 2137MB used, 3983MB available
System DPI Setting: 96 DPI (100 percent)
So yes, I'll consider upgrading my laptop's memory. Too bad the CPU can't be replaced anymore. By the way, even though TravelMate P243 series are part of acer's business lineup, I bought this lower end version mainly for the price and I thought 2 GB memory and 2.3GHz speed are enough for my needs. Oh well, I guess I'm wrong..