on what OS does SPWW2 run best?

[Imp]

Nobody has asked but as you are running windows 7 so old & not supported anymore.
1 Do you have any aftermarket graphic tweaks installed?
2 Have you kept your drivers up to date?
3 What version of direct x are you running?
4 Done the basics, checked hard drive for errors, window install not corrupt & for virus etc
5 Old machine checked your memory etc is still good.

Forget full screen windowed taskbar auto hide off is what you need to use.
Turn off splash screen though think this is now fixed.

Do other games have problems, have you tried running them in borderless gaming?
I do not run winsp in it as no need but winsp & borderless gaming both work fine.
My guess is its not windows 7 its a driver or machine issue as its only you that has this problem.