HELP! Windows Vista issues: freezes, especially audio/video?

I got my computer around March last year. Its a Dell Studio 1555 with Windows Vista. All the programs freeze constantly, especially during typing, and playing videos and/or audio. Following instructions i found on a website, my Administrative events viewer has logged over 30000 errors.I had some computer-literate friends look at it and they ran a defrag, a Ccleaner, a security scan and a few million other things to no avail. I found on the internet that there was issues with Vista as a actual program. What can I do to rectify this? And dumb it down for me, I'm terrible with computers.