How to speed up my computer?

My computer is becoming slower and slower. I need some help on how to speed up my computers boot, run and shutdown time. I am not strongly confident on trying different downloads to fix my computer but if you are 99.9% sure they will work recommend them.

I am running Windows Vista. I think that’s all you need to know to know if the programs or options are compatible.

Well, I had a problem and then I fixed it, but lots of my settings are lost. I always used to have a little thing on my screen show up when I changed the volume using the button on my computer. That no longer shows up. Also, on the taskbar, I used to have a battery meter on the right, just left of the icons next to the time. I would like to get these two things back. My computer is an IBM thinkpad T30 and I’ll give you some details on the problem I had earlier.

I got a bsod when windows tried to load, with the error c0000218 which said that the file c:\windows\system32\config\software could not be found, so I replaced it with the file at c:\windows\repair\software and the computer could then load, but my settings were lost here.
I just remembered something else which actually probably caused the problem. When I was desparately looking for solutions, I went into windows recovery mode and tried the command "fixboot" which said it would create new boot instructions or something like that… It didn’t colve my problem though. I think it might have caused these new ones. Is there any way to go back to the old settings??
one more little detail to add

Here’s the IBM downloads page for my computer. What on here might help me?
http://www-307.ibm.com/pc/support/site.wss/document.do?sitestyle=lenovo&lndocid=MIGR-42358#PA

I’m wondering if there’s a totally free Registry Cleaner and Repair download for Windows Vista. I’ve seen lots of free registry downloads but they all ask you to purchase the repair part after scanning for problems….

My computer is taking longer to load when I simply open my web browser.

I have cleaned my cookies and history, but it still takes a long time to load.

I think I have too much junk accumulated over the years that needs to be cleaned out but I don’t know how…

I tried to download a short clip the other day but I don’t know where my computer saved the file. The program stated that I downloaded it six times, but I have no idea where all those downloads went and I have no idea what they are called.

Like I said, there must be a bunch of junk on my PC that needs to be cleaned up. I looked at some files and folders, but there are hundreds with crazy, illegible names that have no logical meaning to me at all. How is a regular person who doesn’t have a degree in computer programming supposed to be able to maintain their computer??

Yahoo toolbar was installed on workstaions on our LAN. After uninstalling the program I find that windows registry was modified and client downloads are blocked. How do I reset registry?