Thanks. I've cleared the cache but there's no difference. I still have NeixTCoup files showing in App Data/Local/Tewp and there's now 94 files in the location C:\Users\Stan\AppData\Local\Mozilla\Firefox\Profiles\lf6wt0m9.default\cache2\entries
I seem to have got lots of left-over NeixTCoup files and some sort of rootkit which keeps creating these files every time I open Firefox. When I use CCleaner to clear space it takes a long time clearing these Firefox extensions, it never used to do that. I've also got a problem with Windows Updates, it tells me Windows is unable to update and when I try the recommended lines of help and fixes, nothing changes, still the same, browser running slowly and all these NeixTCoup files everywhere. What can I try now please? Thank you. Stan.