A couple of days ago, I started noticing my PC behaving strangely. It seemed slower than usual and had a sort of "studder" - for example, it would delay and then open 2 new tabs when I was only trying to open 1, and delay and open 2 new browser windows when I was only trying to open one. There were also delays when I was typing - I would type and nothing would display, then a second later my text would appear instead of the usual instantaneous typing. I ran a scan with Avast! free antivirus, which turned up nothing. Then I downloaded the latest update for Malwarebytes and ran a Custom Scan. It turned up several instances of PUPs and other problems listed here:
I proceeded to quarantine all items and later I deleted them. Since then, I've run a couple of Malwarebytes Custom Scans over the days since, which turned up nothing. Also, the "studders" appear to be gone and I haven't noticed any more strange behavior. Not yet, anyway.
I'm wondering what more I should do to make sure I am free from this malware, and what I have to do before I can go back to using my computer for things such as Amazon purchases or job applications which may require me to enter personal information.
So far yesterday I've run a Malwarebytes Threat Scan (which I am told is the new name for the old Quick Scan). Like the past couple of scans I've done, it has turned up nothing.
I am using Windows XP Service Pack 3.
For security, I use Avast! antivirus (free) version 2014.9.0.2021
and Malwarebytes Anti-Malware (free) version 188.8.131.522
Any help would be appreciated!