I have no clue what to think after reinstalling FS9. After the install, CD in drive, I fired it up, adjusted the basic settings and did a quick check. Everything worked fine. Next step was to install the 9.1 patch, which gave me no trouble in my last install. CD still in the drive, I tried to fire it up, but got this:

To which I thought, "Duh. Twice as much. So what." The computer just stared back at me impassively. FS9 just hung and steadfastly refused to start. I rebooted the computer and tried again. Same result. I uninstalled FS9, scrubbed all mentions of it from the registry (Micro$oft says it deletes all references from the registry during the uninstall process, but I found at least a dozen entries still in there, which I manually deleted.) I reinstalled, with the same result.
Any ideas? Could it be the patch, or is there some other sinister plot afoot? A hardware issue? All I've done is re-load WinXP-SP3 back on the computer. It's nothing fancy. Dual-core Pentium with integrated graphics and sound. A conflict with... what? MSOffice is the only other thing on the computer so far.