Prevent file access to system32 folder?

[Jmacp]

I keep on getting spyware dll's in my system32 folder. They're impossible to remove without rebooting into safemode(pain) and change my start page and generally slow a pretty slow PC down to a crawling point.

Is there a way to stop access of all files going into that folder.

Firewalls kill my PC and setting the IE options to high stops a lot of pages loading correct.

Any ideas?