I agree with those saying that you should at least get off Windows XP. It's really not supported anymore by MS, and is slow and antiquated. At least go to Windows 7 or something else. If you upgrade before downloading you won't have to download twice...
By the way, what are you using for security? You need a package that runs a firewall, security scans, process monitoring and file cleanup so you have a reasonable chance of not being invaded.
Microsoft security essentials I think it's called. Anyway, I regularly download things, watch videos, use mozilla... my pc is 8 years old ... I never ever had any problems, not a single virus, and the computer is not slow. Never has been. CCcleaner once in a while... I don't know anything about all this stuff but hey, it seems to work perfectly. Never had any lag on chess.com too! 
(don't know if it's relevant but hey, I see folk having all kinds of problems with that...)
The only thing I am a GM at, is cleaning dust from the fans and cards and all that. It's so silent and perfect that I'd rather die than change something. If it ain't broken don't fix it.
Oh so it's not free? After a year you have to pay them,is that right? If so, I would say forget it.