First off, it's normal to have several OS choices; assuming they're both Red Hat Linux kernels, they're just different versions. If you used up2date to update your kernel, the old one is still stored in your /boot directory as a viable, bootable kernel; it just is no longer the default. I wouldn't want to advise you to delete those obselete kernels, since they can be your lifeline if you get into trouble with the latest one (even if that's ten kernel updates down the road). That, and it probably doesn't have anything to do with how slow your system is.
Now, please define what you mean by "slow." Do you mean things are taking a long time to load, or that your mouse pointer is skipping around the screen and even the keyboard seems not to be responding...? Here's a suggestion. Open up a terminal window and type in "top". No ampersand, because you want this to be running in the foreground.
TOP will spit out a list of the programs that are using the most memory and CPU time; if anything looks like it's taking up a lot of resources, you'll need to kill it and note if there's any improvement difference. Here's how to do that, and what to look for.
You see the very top line of the output, on the right hand side? You should see "load average: " and then three numbers. The closer those three numbers are to zero, the better. If they're high, don't worry--that's probably why your computer's slow. Now, look down to the black line, and you should see %CPU %MEM. Under these headings, which stand for "The percent of my total CPU processing power a program is taking up" and "The percent of my total RAM a program is taking up," respectively, you will see numbers that should normally be no greater than 1.3 or so, give or take (and lower for the %CPU numbers).
If a program is running amok and taking up a great deal of your resources (CPU & RAM, &c.), it will be at the TOP of the list (hence, the name, AFAIK; at least it works for me
). So, do you see anything near the top that shouldn't be there, or that's in other words taking up much more MEM or CPU percentage than it should? "top" should itself be at or near the top, because it's monitoring stuff; but even that shouldn't be taking up too many resources. Do you have any programs that are being Ridiculous?
Here's an example. Every five seconds or so, in my "top" list, wget pops up. Wget is a program that is running in the background on my Linux server. Well, it's been mirroring a site very s-l-o-w-l-y (i.e., politely!
) over the past week or so, and it's incidentally now taking up 30.7% of my RAM. If that were not expected, I could then kill that program (force it to terminate) by typing `k' into the terminal window where top is open.
Try it. See that, above the black bar, where it says, "PID to kill: "? Okay, that's asking you, "What is the Process ID number for the program that's going nuts? I'll take care of it for you." Well, you just find the PID (on the left hand side of the screen) of the program that's usurping your resources, type in its number there, and hit enter. It should immediately "die" (be terminated).
Does that help your problem? If so, what program was it that you killed?
[That may have been too involved, and if you already knew how to do that, I didn't mean to insult your level of knowledge; but hey, we were all newbs once.