System Policy / Policy Objects
Hello, me again, with yet more computer trouble. My control panel seems messed up since I had a virus a while back, I can't change my desktop or screensaver.
System policy / policy objects are being utilized on your system, which locks down customization. Enterprise Windows administrators are used to doing such on systems, to prevent all sorts of user customization.
Any idea what could be wrong? I cleared out the virus with a couple of good programs, and I'm not even sure that was what caused the trouble, could it be a setup issue?
Ahhh, that explains it. What you had (and may still have) was a management-type rootkit, one where someone can remotely administer your Windows system as they see fit.
The problem with many of these rootkits is
even when you think you removed them, you often did not, because they hide themselves. As Microsoft has repeatedly told its enterprise customers for the last three (3) years,
reinstallation of the system is highly recommended as it is impossible to remove many types of rootkits once the system has been compromised.
Also, I've just auto-downloaded Windows XP Service Pack Three, whatever that is. When I went to install it I was advised to back up my system, but I have no removable storage. Should I not bother with the update, or is there another way to backup?
There are many ways to backup. You can back up to internal disk, by reserving more storage. There's really no excuse to not backup, so you at least keep your data files.
Although it's not like Windows "restores" very easily, it's one of the chronic flaws/issues with Windows. So, again, all you can really do is backup your data, you'll have to reload Windows regardless if it self-fucks during the update.
I.e., since 2004, when EMC bought VMware, I've made a lot of money at companies who 100% virtualized Windows. Why? Because Windows self-fucks or gets fucked by malware regularly, no matter what you do, and Microsoft has
no feasible disaster recovery options for Windows.
Hell, even Microsoft uses a Red Hat-based (Linux) storage library solutions from FalconStor/Copan for their own disaster recovery (among other things where they either cannot or, in many cases, choose not to use their own software). But that's besides the point here.
You've been compromised, with a full rootkit. It means you
cannot trust your system at all, regardless of what anti-virus vendors tell you. Rootkits compromise core system libraries, so
they can replace the functions that anti-virus kits use and feed them bogus operations, including cleaning/removing files the rootkit protects.
If you really, really don't want to reload, pull up the register with a MMC (Microsoft Management Console) that lets you change policy on system settings until you get your Screensaver and what not. Then reboot, login and reboot again. If you "lose" your Screensaver again, it means the rootkit is still very much active.
As Microsoft started telling enterprises three (3) years ago, reinstall, it should be standard procedure. Microsoft has bought a VM product to try to address the system recovery issues, but as anyone in the industry will tell you, it's the worst of any option and the least complete. That's why VMware has over a 90% share, and over 90% of their installs are for Windows.
Like many things Microsoft and users rely on, VMware is Linux-based -- most specifically, ESX Server 3.x is based on Red Hat Enterprise Linux 3. For home users, running VMware is an issue because it prevents DirectX and many other things from working.
You should consider investing in a Norton utility for reducing the time to reinstall Windows from a known, good point. Unfortunately, that means you need to start taking full system backups, which it sounds like you don't have the storage to do. At this point, try the policy change above and, if it happens again, re-install cleanly. It's what Microsoft recommends very highly by default.
Sorry to hear about your troubles in any case. I see this almost daily myself, and it's why I've made a lot of money ripping out Windows for a dozen years now. This includes at many, many household name companies, especially for computer illiterate people (not yourself, I mean others) who constantly screw up Windows, and need an OS that prevents them from helping the OS fuck itself.