One thing Ive learned is that computers are like cars; you have to take of them on regular basis (regular scans, defragmenting, don't overload them with crap, etc).
Another thing to keep your PC running smoother is don't keep all your files on it, especially music and pics. Both of those fill up a hardrive really fast and start slowing it down really fast. I suggest getting an external harddrive to keep all that stuff on. Basically, if you don't use the file on a regular basis, it doesn't need to be on the HD.
Exactly!!! we have an external drive, with music,videos,pics & misc stuff. It helps alot. I defragment, I run scans everyday early in the am, I leave my pc on 24/7.