If you really want to know just how fast your computer is capable of performing I highly suggest performing a full reformat/reinstallation. That is of course, if you truly find your system lagging. As much as the anti-spyware programs and cleaner-type programs can help scan and remove many things, as well, performing a 'windows repair' installation can make a difference, but if you truly want to see what speed is, you need to start fresh! Personally I find that if I haven't performed a full reformat/reinstall within a one year period then I know I am due. Typically I am performing a windows repair installation (which essentially replaces the windows system files at which point I then perform all windows updates and patches) at about the 6-8 month mode, but when I find that this just doesn't seem to be cutting it, I'll do the full reformat. As I just did with my server as you may have read from previous blogs, I had no idea just how much of a dog/pig it had become! Wow, what a difference... no if only I can get the exchange server and stuff to function through my router correctly... but that's another topic altogether!
Since performing a full reformat/reinstall means wiping the drive clean, you will have to make sure you have everything backed up. For me, I do it in a number of ways. First, I'll use Norton's Ghost program to do a full drive image backup. I then backup 'my account', in my case, to another drive/partition/networked server and to top it off, I have utilized Carbonite's backup system which is something I would truly suggest any and all to go for... think about it.. for $5 dollars a month, I know each and every file on my system is completely backed up.. If I wanted to, after I had done my drive wipe, I could have simply reinstalled windows and run the restore program and everything would be back just the way it was. Although I didn't do this, it may have made things quick again, however in my opinion that would have simply restored everything exactly how it was, which is fine from a data point of view, but I was after reclaiming speed/performance therefore the data backup was done locally, but regardless I always have Carbonite to fall back on! I don't need an entirely new operating system such as windows vista at this point, not when I figure I have reclaimed about 30% of my performance of my machine! Remember my TIPS on OPTIMIZING may help you out and the SOFTWARE/SUPPORT page is full of tweaker tools and anti-removal/cleaner software to download and use!