Here's some advice I gave in another post. I think it may be what you are looking for.
Try going to a terminal and typing the following:
ls -l |less
You'll see something like this:
-rwxr-xr-x 1 root root 893 2003-01-29 13:43 rc.4
-rwxr-xr-x 1 root root 5303 2004-06-21 09:32 rc.6
-rwxr-xr-x 1 root root 1989 2004-06-21 07:04 rc.K
-rwxr-xr-x 1 root root 7906 2004-06-19 20:42 rc.M
-rwxr-xr-x 1 root root 10324 2004-06-19 21:26 rc.S
-rwxr-xr-x 1 root root 466 2004-02-25 16:10 rc.acpid
-rw-r--r-- 1 root root 1605 2004-05-29 13:12 rc.alsa
-rw-r--r-- 1 root root 1032 2003-02-01 19:47 rc.atalk
-rw-r--r-- 1 root root 1031 2003-09-21 12:07 rc.bind
-rwxr-xr-x 1 root root 3949 2003-12-15 13:23 rc.cups
The files that have "x" in the permissions are being started when you boot your computer. You may not be using some of them. Specifically, you probably don't want rc.atalk, rc.bind, rc.dnsmasq, rc.font, rc.gpm, rc.httpd, rc.ip_forward, rc.lprng, rc.mysqld, rc.nfsd, rc.pcmcia, rc.portmap, rc.samba, rc.sendamil, rc.serial, rc.wireless, and rc.yp. Of course, this may vary for you, depending on what services you need/want. To turn these services off, type something like this:
chmod -x /etc/rc.d/rc.bind
You'll just replace rc.bind with the names of the services that you don't want. Reboot, and you should already find less processes running.
Next up, we are going to look at another place that startup programs are also listed. Open up /etc/inetd.conf . Since you are using KDE, you can open that file up with Kate. You'll see a lot of lines that start with a "#". Those are commented out. What we are interested in is the lines that DON'T start with a "#". Those are services that are being run at start time. You need to put a "#" next to the services that you don't want/need. Which ones? Well, I personally comment out just about everything. Comment out the ones that you don't want and reboot. THere should now be even less processes running than before.
The next bit of advice, take it slow. You don't want to shut down everything and find out that your computer doesn't work. Make a couple of changes, reboot, and check things out. THat way, if something goes wrong you'll know where to start looking.