I'll be very straightforward.

I can't download Police Quest: SWAT 1 + 2.
Avast starts going haywire and it nearly takes complete control over my PC after about 600 MB has been downloaded. WIth that, I mean it takes ALL MEMORY my PC has.

I have tried to shut Avast off while downloading, it was still ridicilously slow download and by the end of it, it said that my setup was corrupted.

Is there something I should know about?

Update:

This problem seems related to the Gog downloader as it doesn't go haywire when downloading it "Normally". Interesting to note is that nothing else I've downloaded with the gog downloader makes it go haywire, only this.