My laptop cannot connect to DSL cable connection.So,I think that maybe it because of the registry of my laptop.Can you find me the best registry cleaner that is absolutely free and I do not have to buy it

Well i got a pretty old computer. It had 2 worms once.. and my dad got it to his friend to fix it. When he fixed it he said he wouldnt fix it again.. so now its broken again and i really want to remove viruses without paying..heres some problems

1.SO MANY VIRUSES AND STUFF.
2.WHEN I OPEN A PROGRAM IT ASKS ME WHAT PROGRAM I WANT TO OPEN IT WITH.
3.I HAVE AVG 8 BUT SINCE I CANT OPEN PROGRAM SINCE IT ASKS ME WHAT PROGRAM TO..I DONT KNOW WHAT.
4.JUST MESSED UP I TRUELY WISH TO FIX.

I REALLY WANT TO FIX!!! SO ANY SOLLUTION LIKE A GUIDE TELL ME.
Here my questions:

1.I want to get a fresh new start i got 2 cds..the 1st one says:
DRIVERS AND UTILTIES- ALREADY INSTALLED ON YOUR COMPUTER-DVD for Reinstalling Dell Inspiron 530/530s Computer Software-THe software is already installed on your computer.Use the media only to reinstall the software-Contents Device drivers Diagnostics and utilities-I got windows Xp!

Not one of the stupid trials that will scan and then want you to pay for it before it will fix any of your problems. Thanks.

I have a program (Fix It Utilities 6) that keeps my computer clean and up to date, which also cleans/defrags my registry as well as several other areas of Windows XP. It deleted a few keys it apparently shouldn't have, & now a little box pops up that says "Preparing to Install" before I do ANYTHING. It takes awhile before it will do ANYTHING you want it to. I can't even right click on the desktop & have that little menu pop up until it thinks for a year & looks for the Missing registry keys, then the box pops up "Preparing to Install" & what seems like forever later, it does what you asked. I'm not computer illiterate and I know alot about fixing them, but this one is nuts! I put in my XP CD into the drive and figured I'd do a repair install. Won't work. Tried it within windows, and it just says "XP has encountered a problem and needs to close." Tried to boot it with the CD in the drive. Nothing. And yes, CD is 1st boot device. System Restore…Nothing. NO effect. WTF? What can I do?