Well that's a great news. Glad you got it sorted.
If you manage to do a clean install, i'd choose the 64bit, many reasons are there. Like more and efficient use of memory, better resistance to malware and rootkits (though there's one TDL4 variant for 64bit, but that's the only one till now) etc..
Also, don't forget to do a image of system drive so that in case when disaster strikes (which I really not hope to), you can have your system up and running within minutes. You can use windows inbuilt tool or use 3rd party tools like Macrium Reflect Backup and Hard Disk Imaging for Windows 7, Vista, XP and Server 2003/2008 Backup Complete Computer - Create an Image Backup System Image Recovery
I prefer Macrium because the image created is usually small 4-8 GB's instead of Windows's 20+GB's.