OK to change My Computer / Tools / Folder Options / File Types from IE to Firefox?

I recently cleaned up my PC with help of Ewido antispyware, and have switched from Internet Explorer to Mozilla Firefox as my default browser. I still have some minor popups coming up in IE. If I go to the above location, I see that several types of files are still set to open in IE. These are HTX, HTW, ITS, MFP, MHT, MHTML, SPOP, SVG, SVGZ, SPOP, and XSL files. Can I safely change these to open up in Firefox, or what might be the consequences if I do? I am running Windows 2000 SP4 on a small, older laptop with a dial-up connection. No firewall, but I run various scans all the time to keep my PC clean.

OK to change My Computer / Tools / Folder Options / File Types from IE to Firefox?ds browser

Yes, that that part of your question is perfectly safe.

One watchout: as you probably know, Firefox deliberately does not display/run ActiveX controls. There might be a few web pages who legitimately (albeit misguidedly) use ActiveX - I know by bank does it. For that simple reason, I would keep a copy of IE installed and updated.

Firefox offers an "Display this link in IE" plug-in, that makes this thing really convenient.

However: you should never run a computer without a firewall. Get ZoneAlarm, or get another freeware firewall that's good, and install and run it. You probably know that Windows 2000 is no longer supported (or updated) by Microsoft, so I also encourage you to make upgrade plans sometime soon.

OK to change My Computer / Tools / Folder Options / File Types from IE to Firefox?microsoft templates internet explorer

yes it would be safe but you can make a restore point and system restore to make extra sure.
Your computer was affect by spyware, you need to download a strong spyware remover. Such as Webroot Spysweeper.