The screen keeps asking for my identity and password which I have supplied, but still I am blocked from accessing site. Would telephone someone, but no phoe numbers are listed. Can you help?

i have a windows xp and since about a month ago my internet connection has been getting slower and slower. i have already checked for viruses, spyware, and malware with ca antivirus, and i have cleaned/fixed the registry. the problem started after installing live one care, the computer didn’t have the requirements so i uninstalled it. i have checked the connection with another and the internet actually works fine on that one so i know for a fact it has to be the computer.PLEASE HELP!!!!!!!!

I just downloaded a computer registry cleaner off of download.com. It found over 400 problems. I want to click the "fix it" button to clean it all up, but I’m afraid it will erase important things off of my computer. What do you think?

What is the best utility program for WinXP (like System Mechanic Pro, Norton Utilites, etc.) Freeware, shareware. Cleans your registry, cache, optimization, tweaks, defrag, error fixing, uninstalls, boot defrag, etc.
Thanx!