xp restart/shutdown problem, among others

[havn't a clue]

I have a P4/1.6Ghz CPU, w/768 MRAM.
CD ROMs: ATAPI CD-R/RW and E-IDE CD-ROM
Video: NVIDIA RIVA TNT2 Model 64
OS: WinXp Pro

I just recently re-installed XP Pro and SP1a, and have been having the following difficulties:

1) when I turn on my computer, I get a black screen that gives me the option of either starting XP or starting XP using setup. I have gone to control panel>system>advanced>startup/recovery, and selected the "fastdetect" option. This didn't correct problem.

2) all programs are running much slower w/installation of SP1a. this may or may not be of any relevance, but this particular problem was only noticed after SP1a install. have deleted "hotfix" (sp2) Q322011, 327979, 814995,815484, and net framework 1.1, per instructions from other help sources. no luck with fix.

3) computer will not restart or shutdown from start and will not restart using control+alt+delete. when used in safe mode, these functions work properly.

I would appreciate any assistance in correcting these issues.

Thanks in advance