I have had my computer now for about 3 years and it is running real slow. Is there any free versions to clean you computer completely, so it will run faster?

I have an HP Pavilion 513n with windows xp and it's SOOOOOO SLOW! I want to speed it up and everything on it is useless junk, because we have a new computer, but I don't want to install the sims 2 on mt new computer. will completely deleting everything on the old computer speed it up much? If so, any tips on how to delete everything?

I need something that does it all; ie, registry cleaning, virus targeting,problem-solving,speed-incfreasing,garbage-removing,et
. Kinda like an overall optimizer..

I want to schedule my desk cleanup to run once a week. When I go to the Schedule Task Wizard it eventually asks me for my password. My computer to my knowledge doesn’t have a password. (When I turn the computer on it doesn’t ask for a password and this is the only time it’s ever asked me for a password.) So, I just click next, but then I get this error:

“An error has occurred while attempting to set task account information. The specific error is: 0x8007005: Access denied. You do not have permission to perform the requested operation.

What do I have to do to get the disk cleanup to run as a scheduled task? Alternatively, how can I reset my password or figure out what it is?