Cannot start applications

New user here. This is my second post. I thought I would try to be more clear of what I have going on. Windows XP operating system.

I cannot start applications. Some start, some don't. The hour glass appears for a short bit, then disappears. Nothing.

Examples of applications that will not start include: MSword, Msexcell, MS Internet Explorer, Hi-Jack This, MalWarebytes Anti Malware. I downloaded AGV 8.5, but the system will not let me launch the downloaded file. Many others.

Also, I cannot remove programs using control panel.

Things seemed to go to heck after daughter was using windows messenger. Not sure. She normally would use laptop.

Examples of applications that will start include: Mozilla Firefox (I can use the web without problems.) Quake 3 works. I mention Quake 3 because 1 week ago, all was fine but I could not launch it. I ran AGV 7.5 and the trojan horse SHeur2.zGY was quarantined. Quake 3 still would not launch and I downloaded and ran MalWarebytes. All was OK. Until yesterday.

Following the steps of your Malware Removal Guide:
STEP 1 House Cleaning:
* Do not use multiple Antivirus applications or software firewalls: AGV only, no firewall.
* Uninstall Malware via Add/Remove Programs: Although I do not see anything that sticks out, the system will not let me remove any programs.
* MSconfig must be set for Normal Startup Mode: Done
* Empty Quarantine files: Done (AGV)
* Empty Recycle Bin: Done
* Download and Install CCleaner: Already have ccleaner on system. The application will not launch.
STEP 2 Enable Viewing of hidden files, system files, etc.
* Complete.
Windows XP Cleaning Procedure
1. Download Tools
* Super AntiSpyware - OK
* Malwarebytes Anti-Malware - OK, already on system
* combofix.exe - OK, Downloaded to desktop
* MGTools - OK, downloaded to root (C:\).

Step 2
Installing Tools
SUPERAntiSpyware - Will not launch
Malwarebytes - Will not launch

I stopped here.

Please help.

 

Yes, I tried to rename files to get them to run. Very few *.exe files will run.
Systems acts the same in SafeMode, Cannot run *.exe files.
MGtools will not run. It is a *.exe file. Will not run in SafeMode either.

I did get Norman to run, but not in SafeMode. When it was done, I could not copy the results. The option did not exist. It did found the virus SHeur2.zfy. I rebooted and tried to run it again in SafeMode and normal boot. The application did not launch. So I uninstalled it and tried it again. It launched and found Virtumonde.axct. This time, before rebooting, I scheduled it to happen automatically in a few minutes. I rebooted and after a bit, it automatically started. This time, no viruses were found. If I try to launch Norman again, I just get an hour glass.

This computer has been in my life for at least 5 yrs+ and never had a problem. Maybe it is time for a fresh install. Any suggestions for a final try before I do it?