Windows Explorer & IE crashing constantly on a fresh install?

Start with these free diagnostics:

H/W Diagnostics:
Please start by running these bootable hardware diagnostics:
Memory Diagnostics (read the details at the link)
HD Diagnostic (read the details at the link)

Also, please run one of these free, independent online malware scans to ensure that your current protection hasn't been compromised: Malware (read the details at the link)

Then, if the above tests pass, I'd try these free stress tests:

FurMark download site: FurMark: Graphics Card Stability and Stress Test, OpenGL Benchmark and GPU Temperature | oZone3D.Net
FurMark Setup:
- If you have more than one GPU, select Multi-GPU during setup
- In the Run mode box, select "Stability Test" and "Log GPU Temperature"
Click "Go" to start the test
- Run the test until the GPU temperature maxes out - or until you start having problems (whichever comes first).
- Click "Quit" to exit

Prime95 download site: Free Software - GIMPS
Prime95 Setup:
- extract the contents of the zip file to a location of your choice
- double click on the executable file
- select "Just stress testing"
- select the "Blend" test. If you've already run MemTest overnight you may want to run the "Small FFTs" test instead. (run all 3 if you find a problem and note how long it takes to error out with each)
- "Number of torture test threads to run" should equal the number of CPU's times 2 (if you're using hyperthreading).
The easiest way to figure this out is to go to Task Manager...Performance tab - and see the number of boxes under CPU Usage History
Then run the test for 6 to 24 hours - or until you get errors (whichever comes first).
This won't necessarily crash the system - but check the output in the test window for errors.
The Test selection box and the stress.txt file describes what components that the program stresses.