Thanks for all your replies! Downloaded and ran the ATF program, which removed 150kb. I'd already been clearing IE and Firefox caches to free space, but this is quicker.
Stopped Skype, Yahoo IM, Windows Media Ctr network sharing svce config app, iTunes, GoogleTalk, Adobe Acrobat and Realplayer from starting automatically at startup. Also tried dumping some files - 5gb out of 111gb are now free. I'm still trying to get to 15-17gb total free, but have sooooo many files.
The window still stays black after startup, but now it's only 2 minutes vs. 25 minutes. Still, the 2 min. delay (and font change) worries me. Is there any more troubleshooting I can do besides defragmenting?
Can I/should I suspend any of these other programs still running at startup? Are any known to cause trouble? They are: three Intel Common User Interface programs (igfxtray.exe, hkcmd.exe and igfxpers.exe) and Intel's RAID Event Monitor (Iaanotif.exe), QuickTime (QTTask.exe), Java polatform SE 6 U11 (jusched.exe), GoogleToolbarNotifier.exe and GoogleUpdate.exe. Thanks again!