Internet and printer not working on Windows XP desktop

Please note that this is a different computer from my similar post about my laptop and that's why I'm posting in a different thread. Strangely, the internet problems on both PCs started at the same time.
My desktop is hooked up to the internet through my parents' router, but their internet has remained uninterrupted throughout. I'll open Internet Explorer, but I get an error message saying Internet Explorer can't connect to the web page. I had a similar problem with Firefox.

The printing problem pre-dates the internet problem. It's a brand new Canon printer, but I get error messages indicating that the system can't find the printer when I try to print something (although the printer's name is still visible in the print dialogue box). I even sent the first new printer back to the manufacturer and got a new one, but the same problem just cropped up again.

I also often get a Windows error reporting message at startup, saying some errors happened with some software I used previously, but the errors weren't reported then (it never says what software had the errors).

I ran the "Read and run me first", and I tried to follow them precisely, but there were a couple of problems. Since I didn't have internet, I printed out the instructions on my parents' computer, but they printed without the screenshots and the written instructions did not always match what I saw on-screen.
When I ran HitMan Pro, I didn't see any option to "IGNORE", so I thought maybe it was defaulted to ignore. So I clicked next and it went ahead and deleted and quarantined stuff even though the instructions said not to. There didn't appear to be any way to undo. Then there was no "Save Log" link, so I thought it might be on the next window and I clicked "next" and the log went away without saving and there was no way to go back. So I wrote down what was listed under history:
{9AFB8248-617460d-9366-D1CDEDA179}\
HKLM\SOFTWARE\ClassedCLSID\ Deleted
brrot-uninst.exe Riskware Quarantined
YontooIE Client.dll Malware Quarantined
C:\Program Files\Yontoo\
The instructions said not to run it again, so I didn't, hoping the above history might be enough for you?
Then I had trouble with Malwarebytes. The instructions said to close the Notepad log report and look for it in the hard drive, but I could only find old reports there (I've used it before). I swear I looked very carefully and even ran a search on the hard drive and it didn't find it for some reason. So all I could think to do to get you that report was to run it again even though the instructions said not to, then save the report manually. I hope this isn't a huge problem; I got the feeling the instructions might have been for older versions of HitMan and Malwarebytes?

Anyway, the internet seemed to come back right after that, but then it was gone again by the next day. I found I've been able to get the internet back briefly by holding down the F8 key at startup and choosing the last settings that worked. Even then, after a couple of hours, I'll find that when I go to another page within the site I'm visiting, or when I go to a different site, I'll get the same old error message.

I tried to attach the logs to this, but it failed; the error message said it needed a security token. I'll try it from my parents' computer after this. I hope someone can help with this if it is malware.

 

I had burned the logs on a CD on my computer and brought that CD to my parents computer to upload them from there, but my parents' computer thought it was a blank CD.
That's the way I had done it with my internet problems on my laptop, but their computer had no problem with my laptop's CD.
Their thumb drive doesn't seem to be working either.
So I'm back on my computer to try again. It worked on the text files, but the MG.zip file wouldn't upload; I got the same security token message. I checked the MG.zip's properties and it's 10.6 megabytes. Do you want me to unzip it and zip it again in smaller chunks?

 

I figured I'd go ahead and try uploading MGlogs in smaller chunks.
I got everything up except for the zafind text file, even when I zipped it by itself. Same security token problem.
Unzipped, zafind is 68,425 KB and zipped, it is 10,699 KB. Any suggestions on anythiing else I can try to get it to upload?