When installing ASP.Net, the Framework, or for that matter, any new app, here are some things you need to check first, just to make sure you get a good installation:
1. Temporarily disable virus protection
2. Remove All Temp Files
3. Make sure no other app is running
4. Run chkdsk/scandisk/Norton’s WinDoctor, or some other fix-it app against your HD to make sure it’s in the best shape it can be.
5. THEN – try installing