I'm having a problem with being unable to open Windows 7 Task Manager with any method. Here is the time sequence.
1) Recently had downloaded Process Explorer to see how it worked. Decided I didn't like it and removed it (oddly, wasn't on my Remove Programs list and had no uninstall file).
2) Needed to use task manager, did Ctrl-Alt-Esc and nothing. No messages, no task manager, no apparent attempt to run task manager.
3) Tried the same thing with Ctrl-Alt-Del and selecting Run Task Manager. Again, nothing. No messages.
4) Scanned my system with multiple malware and anti-virus programs (reputable ones). No changes.
5) Checked the registry for remnants of Process Explorer and removed. No change. Ensured Task Manager wasn't disabled in the registry.
6) Tried to run Task Manager from the taskbar. Got an error on taskmgr.exe "The parameter is incorrect."
I can only assume this is the problem, however I cannot find any fixes for it. Any suggestions?