Here is how I'e gotten all 12 of my computers running NF with minimal (1 a week avg) crashing:

Things I've found about NF:
It doesn't like alt-tabbing during loading.
It easily gets fragmented on your hard drive. Defrag frequently (You should be doing this anyway at least weekly if not monthly)
If nf incorrectly patches one file, it never patches correctly again and will eventually get to the point of mass crashing.
NF and DEP Don't Like Eachother.
NF is more stable in C:/Program Files rather than C:/Program Files (x86), (The folder names do nothing since the programs themselfs call for the 64 or 32 bit drivers and runtimes)
NF, like many programs on Vista and 7, must be run in Admin
Disable Visual Themes, NF doesn't like the Aero Visual Theme stuff.
Defrag the hard drive containing NF regularly
Reinstall NF monthly if you experience(d) high numbers of crashing problems in the past and/or present.
Compatibility modes rarely fix things for most people, they do however increase lag on sometimes.
Installing NF in admin makes a hugh difference on how stable the game runs.
NF on 32 bit systems likes having 2 gigs of Ram
NF on 64 bit systems likes having 4 gigs in Dual Channel or 6 gigs in tri-Channel
NF likes P4 HT processors (Only system where I never had NF Crash once)
NF likes AGP graphics cards.
NF Like having the entire Direct X series from direct X 7 to 11 installed (Latest End-Used Distrubutable installs all of these)
NF loves eating RAM. Have plenty clear.
NF loves eating Pagefile. Have plenty clear. (Even if you have 16+ gigs of RAM, put in at least 2 Gigs of Pagefile per drive)
NF runs better on SATA Harddrives and SSDs (Due probably to faster access to Pagefile)
NF Hates media software in the background, mostly Windows Media Player.
Using X-Fire In-Game with NF actually increases crashing (NF doesn't like Overlays)
Installing .Net Framework 2 then Last SP for Framework2, followed by .Net Framework 3, then 3.5 then SPs for 3.5 then 4 ect help NF since it uses older .Net Framework files.
Up-to-Date Graphics Drivers when using Zoom and/or Anti-Alaizig (Sorry Forgot how to spell it)
NF doesn't like running with Browsers and Email Clients and many other programs that use high RAM/Pagefile usage or access the internet frequently.
Proper Routing by your ISP to the servers helps a ton with Lag and Dropped packets and quite a few annoying, minimal bugs.
Keep-You-Computer-Cool, NF Heats your RAM and harddrives significantly.
NF Like Runs more stable on systems with Odd Number of procressor Cores: Single Cores, HT, Triple Cores) Whereas HT acts more stable (NF Is single Thread Program and can only use 1 Thread Anyway)
Since removing hackshield. Defrag the harddrive NF is on.
Defrag after patches whenever possible. Keep NF on smaller Partitions.
NF likes hogging resources so keep other programs that do the same off.
NF only makes 25 FPS, so you be surprisd your Latest and Greatest Graphics cards aren't making any more frames.

I'll add more when my Carpel Tunnel Stops hurting........