Ok it will speed up your computer, but sometimes it is not the best idea. E.g. On Windows7 32bit you can only make use up to 2.7 gb ram. On xp 32bit a little bit more, but because of the 32bit there is a limit of adressable memory at 4gb. What i have seen recently were people with notebooks with 5400rpm harddiscs, so changing the harddisc to a faster 7200rpm model brought a lot of additional speed. Changing the cpu may also improve the performance, but if the performance bottlehole is the harddisc you will not see much improvement. Check you windows performance index, it might give you an indication what hardware component to upgrade.

Ok it will speed up your computer, but sometimes it is not the best idea. E.g. On Windows7 32bit you can only make use up to 2.7 gb ram. On xp 32bit a little bit more, but because of the 32bit there is a limit of adressable memory at 4gb. What i have seen recently were people with notebooks with 5400rpm harddiscs, so changing the harddisc to a faster 7200rpm model brought a lot of additional speed. Changing the cpu may also improve the performance, but if the performance bottlehole is the harddisc you will not see much improvement. Check you windows performance index, it might give you an indication what hardware component to upgrade. Based on your computer hardware i will guess that most overall improvement you will get from a faster harddisk or solid state disk. If you run a lot of graphic intensive programs (e.g. games) a better graphiccard will increase performance in these applications.