This thread is getting lots of google hits for AppCrash since before Windows 7 was released so needs to be updated. But to get more specific help you'd want to start a new thread.
Sounds like a good plan bangades. We call that a diagnostic install.
Follow the steps for a perfect Clean Reinstall - Factory OEM Windows 7,
But after install only install the Network driver
to get online, then enable Automatically deliver drivers via Windows Update (Step 3)
and do all rounds of Important and Optional Windows Updates.
After each reboot for Updates, test performance long enough to know its okay, then Check for Updates again until all of them are done and no more are offered.
Then do the same with Programs, one by one with testing in between each.
At the point where the problem surfaces, post back a new thread with the culprit you've isolated, System Restore to before it was installed or changed.
Once you have a stable install all set up, save a backup image so you can reimage if it becomes irreparable again. Backup Complete Computer - Create an Image Backup
To test hardware and go over an install after its set up use the Troubleshooting Steps for Windows 7