Welcome to the Fusion 360 community!
I'm sorry to hear you're having difficulties running Fusion 360. I've moved this post over this board where it may see more appropriate traffic.
The system requirements for Fusion 360 may be found in the below link.
http://knowledge.autodesk.com/support/fusion-360/troubleshooting/caas/sfdcarticles/sfdcarticles/Syst...
Do you know if your machine meets the requirements for the 512 MB of dedicated video memory? I ask, because I'm wondering if the original crash was caused by a video memory issue.
The most common fix for video issues is to update the display drivers for the graphics card (see the Intel, AMD, or NVIDIA websites for details). You may also review the below link for a setting that will enhance the performance and stabilty of Fusion 360.
http://knowledge.autodesk.com/support/fusion-360/troubleshooting/caas/sfdcarticles/sfdcarticles/How-...
Some additional tips may apply to the OS itself. There are several suggestions in the below link to optimize the experience on Windows 7. I would like to highlight that disabling the Visual Effects can be a great way to squeeze a little bit more memory/performance from an older video card/system.
http://windows.microsoft.com/en-us/windows/optimize-windows-better-performance#optimize-windows-bett...
When you say you tried a clean reinstall, does that mean that you used the procedure outlined in the below link to uninstall Fusion 360 prior to re-installing?
http://knowledge.autodesk.com/support/fusion-360/troubleshooting/caas/sfdcarticles/sfdcarticles/How-...
Did you skip any step or receive any error messages that may have interfered with successfully completing the clean uninstall procedure? It is critical that each step is completed for the clean uninstall procedure to work.
After performing the clean uninstall, grab a fresh install from the below website.
http://www.autodesk.com/products/fusion-360/overview
Before launching the installer, try disabling any active anti-virus software and unnecessary applications.
I hope this suggestion helps. Please let me know if you have any questions.
Thanks,
Nathan Chandler
Principal Specialist