New Sata hard drive
Think about replaceing the HD in my own PC as it just seems to be the one component that is slowing the system down, always seems to be accessing the HD and just churns away for a while sometimes before catching up with itself, its a P4 3.0Ghz with 1.5Gb of Ram and XP Pro , use it for allsorts except gaming (any way of checking whats the bottle neck?) anyway, looked at a 500Gb 16Mb disk of ebuyer quite cheap at the moment but it says its SATA2, and the age of my PC I guess it would be SATA1, so would the new drive work with SATA1?
Yes the new drive would work with SATA 150 so long as the jumper is in place on the drive, other wise it'll run in SATA 300 (if the motherboard is compatible).
To be honest if the CPU is constantly processing and you see lots of hard disk activity, it's more than likely a lack of memory as Windows is using the swap file or virtual memory as it's referred to.