I think I may have permanently messed up my 2006 MBP...
I noticed while using Mavericks that the scroll bars would just randomly disappear. I thought it was just an issue with Discord on FireFox 78, but this issue also appears in other sites as well as Finder. So, I downgraded to the patched Mountain Lion using an image I had made and all was well until I tried to reboot into XP. I reinstalled rEFInd (like I normally do when changing my OS config on an Intel Mac, but it's boot menu wouldn't show up despite rebooting three times (it is only supposed to take two reboots for the menu to appear installation, sometimes it works after just one reboot). So I tried using ML's startup disk control panel to get into XP. When I did this XP BSOD'd, I couldn't even get into safe mode. So, I wiped the SSD and started over with a fresh install of Leopard and XP via BootCamp Assistant. It took the Mac about 5-10 minutes to reboot into Leopard after installing the Bootcamp drivers. Even my SL Install DVD took about 10 minutes to boot to its desktop. I wiped the SSD, still slow booting. I reset the PRAM, still slow booting, I reset the SMC two times, still slow booting. I repaired permissions and repaired the SSD itself via First Aid (even though First Aid said the SSD was fine), still slow booting. This slow booting only happens to OS X (both on the SSD and Install DVD), Windows boots normally. Guess I should have let the patched Mavericks be or should have not used patched ML's Startup disk panel to get back to XP. Guess I will have to just make it a Windows only laptop *sigh*.