Stop shitting on him for using Linux. He wants a solution, not criticism. If more people knew about Linux, I bet more people would want to use it. The only thing stopping people is that the average consumer only knows of the bad of Linux; usually thinking it has a lot of Terminal stuff and very little GUI.
Modern distributions are incredibly user friendly and have more than enough software for somebody who uses an older desktop or a netbook.
Enough of that. You may need to do a number of things:
Get RAM - check how much you are using
Update all your packages - apt-get update
Compltely reinstall - something may have been corrupted