Hesitant in Upgrading PC?

[AbdullahG]

I decided to upgrade my PC with a new motherboard, CPU, and RAM. I'm just afraid I will screw up. If I replace these components, what affects should I expect? Will I lose my data? If I screw up, is my PC screwed as well? I just need some advice!

 

[Outlander_04]

you will probably have to reinstall windows [ and all your data ], and if you are using an OEM copy of vista or 7 you will have to buy a new copy