I've tried everything, but I'm still stuck.
I've been having trouble with my computer. When I'm in Windows XP (Home Edition), some of my programs refuse to start after I click to open them. About the same time this started, I was getting runtime & dll errors with a lot of my games and programs, even after reinstalling them. I ran my computer though every online and offline virus/spyware/trojan scan I could think of (though one of the programs that won't run is CCleaner), but they've all come up clean. I've been doing research, and it sounded like it might be a corrupt user profile, (I've done a lot of simple tweaking in my registry, but nothing lately) so I created a new profile and tried to run the programs under that one, but they still wouldn't work.
Now, right before this all started, I was having trouble with Windows Update - it would download the updates, but it wouldn't install them. I tried everything but ended up going to Microsoft's download center and installing each security patch manually. Some of my research had indicated that one of those patches caused problems simialr to mine on other users' computers, but I installed the fix for that and still nothing changed.
I did also recently install Windows Vista on a seperate harddrive on my computer (My Dell is set up to dual-boot), so I don't know if that would affect it somehow. Personally, I think the problem might've started before that.
I've looked in Microsoft's Event Viewer (Control Panel, Administrative Tools, Event Viewer) And only a few noticeable things pop up. One is my attempts to run CCleaner.
One entry says: "Faulting application ccleaner.exe, version 22.214.171.1242, faulting module ntdll.dll, version 5.1.2600.2180, fault address 0x0000316c."
Another entry is for one of my games that refuse to run: "Faulting application vampire.exe, version 0.0.0.0, faulting module engine.dll, version 0.0.0.0, fault address 0x00095ef1."
Last night it recorded this, though it didn't seem to affect the problem in any way:
"Windows saved user COMPUTERNAME\Username registry while an application or service was still using the registry during log off. The memory used by the user's registry has not been freed. The registry will be unloaded when it is no longer in use.
This is often caused by services running as a user account, try configuring the services to run in either the LocalService or NetworkService account."
Also, my firewall (tinysoftware's PersonalFirewall 2005) pops up with an error on startup even though it seems to run fine: "This application has requested the Runtime to terminate it in an unusual way. Please contact the application's support team for more information"
And though it seems to be running fine, I can't open any windows of my Anti-Virus software (Symantec Antivirus).
It's strange that some programs will work and others won't. they are always the same programs. I am running a P4 2.4GHZ Dell Dimension 4550 with 768MB RAM and in the many years I've maintained it, have never had such a frustrating problem with it.
I think that's all the information I have. The only thing I can think of that I haven't tried is doing a Windows repair install, but I left the cd at my house and had to have it mailed to me. (Plus I'd really like to avoid that if I can) I can also post a log of HijackThis if anyone thinks it will help.