A common source of SP2 install problems result from user confusion durin' the install process. See
Microsoft: Detailed installation walkthrough for Windows XP Service Pack 2. Note in particular the warnings concerning the restart prompts offered by the Insatal Wizard (Gee, thanks, Microsoft
)
Of course, if you already have a problem, knowin' how to have prevented it before you began the process which caused the problem isn't likely to be of much help to ya.
Have you tried accessin' Control Panel while in Safe Mode? Shut off your machine, wait about a minute, then restart it. Begin tappin' F8 on restart. The "Windows Advanced Options Menu" eventually appears. If you begin tapping the F8 key too soon, you may get a "Keyboard Error" notification; if so, just restart the computer and try again, waitin' just a bit followin' power-up before tappin'. When you do get to the boot menu, which will be black and white text only, use your keyboard up/down arrows, select "Safe mode" (there are other options, but for this, select just plain "Safe mode"), and click "Enter". The machine should then start in Safe mode. When it does, see if you can access Control Panel. Often that will work. If it does, you should be able to access Control Panel and Add/Remove Programs.
Yoiu might wanna try an overlay, or repair install, of XP. See
Microsoft: How to perform an in-place upgrade (reinstallation) of Windows XP
Anyhow, it should not be necessary to concern yourself with SP1 if you have SP2. Also, even if instalation failed, SP2 should have set a restore point which should allow you at least to get back to where you were before you ran into problems. An aside - I've found usin' the SP2 disk a lot more reliable and trouble-free than relyin' on downloaded SP2.
Free XP SP2 Install Disk
I dunno what method you used to install/uninstall SP2, but the followin' procedure will do a pretty thorough job of removin' it:
Perform a clean boot
When the machine has booted, click Start>Run - type (without the quotes) "C:\windows\$NtServicePackUninstall$\spuninst\spuninst.exe" into the dialog box and click "OK". When the Removal wizard opens, click "Next". Follow the onscreen instructions and reboot when done - still in clean boot configuration.
Use System Restore to revert to a point prior to your problem.
Start>Help and Support>Pick a task>Undo changes to your computer with
System Restore. Select the "Restore my computer to an earlier time" button and click "next". You'll see a calendar on the lefthand side of the System Restore Utility control panel. Dates in bold indicate available restore points. Select one earlier than your first attempt to install SP2 (you may have to page back the calendar to the previous month - use the arrows flanking the nonth displayed atop the calendar to do so), click "Next", and follow the onscreen prompts.
When the machine has rebooted, go back into the System Configuration Utility ( Start>Run - type (without the quotes) "msconfig" into the dialog box, click "OK" and be sure "Normal startup .... " is selected. If not, select it, click "Apply", click "OK", and reboot as prompted.
Finally, Microsoft offers a toll-free number for SP2 install issues:
(888) SP2-HELP (772-4357). Weekday hours are 5:00 AM - 9:00 PM, Weekend hours are 6:00 AM - 3:00 PM US Pacific Time.
Sure hope somethin' here helps ya.