Welcome to LQ
Your question is VERY difficult to answer.
First of all, I found that ubuntu tended to run slower on my computer then slackware. Slack does not have lots of added stuff and is more bare bones then ubuntu. Linux has a steep learning curve and slackware an even steeper learning curve.
All I can do is give you some suggestions on how to speed things up. Perhaps you have too many things running at the same time taking up memory.
These suggestions will probably be beyond beginner level, but it may help.
First of all open a terminal and type "top".
That will give you a list of all of the running daemons and how much memory they are taking up.
Try to remember what you had installed these past few months and remove them.
I suggest to disable some of the start up scripts of programs you do not want. It has been over a year since I used ubuntu or any other debian based distro so I can only go on memory. But, to disable the startup scripts you need to look in /etc/rc2.d or /etc/init.d/rc2.d.
I suggest to google startup scripts ubuntu or look on the ubuntu forum.
Another suggestion would be to use ubuntu xfce for older computers instead of ubuntu gnome.
Last edited by okos; 01-10-2009 at 11:58 PM.