I recently "upgraded" to windows 64bit. Heres some advice: dont go 64bit. You need to download drivers for lan, graphics card, motherboard, chip etc. Also there aren't so many essential applications which work with it. I have to use these crappy firewall because there are like none compatibloe with 64bit and I had to use another crappy anti-virus program which I just uninstalled. You will also findother applications won't work with 64bit. They give you a 32bit media player but you do get a 64bit internet explorer which I don't use. I'm going back to 32bit as soon as i can.
Just don't take a leap into the dark void of 64bit.