If this is an in-place upgrade of the bloated HP preinstall then I would strongly consider getting the superior Clean Reinstall following the same principles as in Clean Reinstall - Factory OEM Windows 7.

Otherwise at the minimum I'd Clean Up Factory Bloatware.

If that isn't sufficient work through these Troubleshooting Steps for Windows 7.

If nothing else works the trace Britton offered will almost always pinpoint the cause, although I'd want a really clean install anyway.