I have a virus in Task Manager It opens Task Manager in the processes page and then opens many CPU usage windows in taskbar. Help needed.
I have run scheduled boot scan but to no effect.
Welcome to the forums, mick66. 
Please download HijackThis from the link below, run the program but do not make any fixes, and then post the log results using the “copy & paste” method. It will probably take more than one post to be able to get the complete log posted. OR, you can post it as an attachment to your post by clicking on “Additional Options…” below left of the posting box. Someone will review your log and then offer help.
http://filehippo.com/download_hijackthis/
There may well be something that intercepts the call to task manager, C:\WINDOWS\SYSTEM32\Taskmgr.exe, you could try this, find taskmgr.exe and right click and select Copy. Now open a temporary folder (create one TmpSySFiles in C:\ would be good to create) and Paste the file into it.
Rename the file Taskmgr1.exe, this should allow you to run Task Manager by double clicking it, when it is open see if there are any unusual processes running and report them.
There are a number of trojans, etc. that actually disable the Task Manager so you can’t open Task Manager and shut them down. These can also block other system tools like regedit.exe and MsConfig.exe, so if regedit or msconfig don’t work you can do a similar trick with those files I mentioned, copying them, paste into the folder and renaming them to regedit.com and MSConfig1.exe. That should also allow you to use those tools to look for installed malware and rectify it.