System unable to start programs after variable amount of time

Since about a week now after a variable amount of time my system is unable to start programs that aren't already running. Some of the already running also crash when this happens. Shutting the system down or restarting in this state is impossible, the system seems to try but doesn't succeed. When I try it command line via the shutdown command the countdown starts and finishes but the shutdown stals when the system tries to log the current user of.

What could have happened to have caused this? I'm not sure, the only program I installed before this started happening is the open source game widelands (http://xoops.widelands.org/) which does have a tendency to crash in a very unclean fashion.

I did all the steps from the Windows XP Cleaning Procedure and have attached the logs. Except the one for AVG Anti-Spyware. When I did that scan my system got in the state described above. It did finish the scan, I was just unable to export the report (maybe that happens in a different thread or something?). The scan ended up quarantining one item: Adware.dudu located in c:\windows\system32\pCastCtl.dll . If you need me to redo the scan I will, I just wasn't sure if it was needed (and it's quite a long scan )

I'm not sure if this is a malware problem but it could be. Thanks a lot in advance for your help.

 

First of all: thanks a lot for your time

Now things I've done:

1) uninstalled the Java part you insturcted me to
2) the guest account already was diabled
3) C:\WINDOWS\TEMP\MB90F4.EXE isn't there? I checked what is there and it's a bunch of extention-less files with names: ibxx where xx is two-digit number. All these files have a size of zero. And a executable called QK3868.EXE of which I don't know what it is.

Okay now on what I have to do now:

1) Will booting from the install cd and repairing fix the problems (or attempt to fix) I am am having?

2) I never installed SP2 due to it's huge bugs with USB drives and because it mostly consist of a bunch of software I'm only going to end up disabling after the install (like the windows firewall). Did you instruct me to install SP2 to fix the problems I am having or just from a personal preference? And would you still advise me to install it anyway?

 

1) I used CCleaner to remove the temporary files.

2) to run "sfc /scannow" I need the windows XP proffessional cd-rom since I downloaded that (legally via a student website called ma3d.com) and no longer have the correct cd I downloaded a version of windows Xp I thought I had and mounted it but it refuses to do scan stating I have to insert the cd.

These are the versions they allow me to download:

Code:

    * Windows XP Embedded with SP2 - Evaluation Version (English)
    * Windows® XP Embedded Service Pack 2, Multilingual User Interface (English, Multilanguage)
    * Windows® XP Embedded with Service Pack 2 (English)
    * Windows® XP Home with Service Pack 2 (Deutsch)
    * Windows® XP Home with Service Pack 2 (English)
    * Windows® XP Home with Service Pack 2 (Español)
    * Windows® XP Home with Service Pack 2 (Nederlands)
    * Windows® XP Multilingual User Interface Packs
    * Windows® XP Professional (Deutsch)
    * Windows® XP Professional (English)
    * Windows® XP Professional (Français)
    * Windows® XP Professional (Nederlands)
    * Windows® XP Professional Checked/Debug Build (English)
    * Windows® XP Professional with Service Pack 1a, Windows® XP Media Center Edition 2004 Disc 1, Windows® XP Tablet PC Edition Disc 1 (Deutsch)
    * Windows® XP Professional with Service Pack 1a, Windows® XP Media Center Edition 2004 Disc 1, Windows® XP Tablet PC Edition Disc 1 (Français)
    * Windows® XP Professional with Service Pack 1a, Windows® XP Tablet PC Edition, Disc 1 (Deutsch)
    * Windows® XP Professional with Service Pack 1a, Windows® XP Tablet PC Edition, Disc 1 (English)
    * Windows® XP Professional with Service Pack 1a, Windows® XP Tablet PC Edition, Disc 1 (Français)
    * Windows® XP Professional with Service Pack 2 (Deutsch)
    * Windows® XP Professional with Service Pack 2 (English)
    * Windows® XP Professional with Service Pack 2 (Français)
    * Windows® XP Professional with Service Pack 2 (Nederlands)
    * Windows® XP Professional with Service Pack 2 (Spanish)
    * Windows® XP Professional with SP1a, Volume License Version, Windows® XP Tablet PC Edition, Disk 1, Volume License Version (Deutsch)
    * Windows® XP Professional x64 Edition (English)
    * Windows® XP Service Pack 1, Microsoft Plus 98 (Deutsch)
    * Windows® XP Service Pack 1, Microsoft Plus! 98 (Français)
    * Windows® XP Service Pack 1a (Deutsch)
    * Windows® XP Service Pack 1a (English)
    * Windows® XP Service Pack 1a (Français)
    * Windows® XP Service Pack 1a (Nederlands)
    * Windows® XP Service Pack 2 - Network Install (English)
    * Windows® XP Service Pack 2 - Network Install (German)
    * Windows® XP Service Pack 2 (English)
    * Windows® XP Service Pack 2 (German)
    * Windows® XP Service Pack 2 Customer Support Diagnostics Tools (English)
    * Windows® XP Service Pack 2 with Advanced Security Technologies (Deutsch)
    * Windows® XP Service Pack 2 with Advanced Security Technologies (Français)
    * Windows® XP Service Pack 2 with Advanced Security Technologies (Nederlands)
    * Windows® XP Tablet PC Edition Multilingual User Interface & Recognizer Pack (MUIRP) (English)
    * Windows® XP Tablet PC Edition, Disc 2 (Deutsch)
    * Windows® XP Tablet PC Edition, Disc 2 (English)
    * Windows® XP Tablet PC Edition, Disc 2 (Français)

I chose * Windows® XP Professional (English) can you see if that is correct? If so I'll try burning it and see if the problem is the mounting process:

3) As an antivirus I use: Trend Micro office-scan v 7.0

 

Okay with that one sfc /scannow literally says I inserted the wrong cd were the first one just says it might be.

I found a very old copy of windows Xp I burned with which "sfc /scannow" did run (it's not the cd I installed this install of, it's of a previous system I have).
When the scan finished it didn't offer me feedback of any kind. Does that mean it didn't find anything wrong, or did it just autofix things?

Also which cd should I use if I'm going to boot form the Xp-cd to do a repair? The cd I downloaded first [Windows® XP Professional (English) ] seems to make the most sense. Also can i just try them all until one works?

Anything else i should know or do?