Computer Issues

So I found out yesterday or the day before that I have a majorly infected computer with malware and viruses galore. Fantastic. It had gotten to the point where I literally could only access Microsoft Word and nothing else...no internet, no Microsoft Paint, no GIMP (similar to Photoshop), nothing. So yesterday I was downloading software and running three or four full scans on my computer, feeling like I had only a quarter of a computer. I became really freaked out, especially since my mom's promised me a laptop for graduation and WILL NOT UNDER ANY CIRCUMSTANCES change the time I receive it. So even if this computer I'm using exploded in my face right now, I still won't get a new one until a year and a few months from now. 

I should also add that it's unfair on our part how software companies offer people a free download of their software, without telling them that if they want to actually GET RID OF the viruses or malware or whatever, they have to purchase the full version.

*Sighs* Well, later yesterday, I was able to use my computer again...with complications. I was so busy trading punches with my computer that I can't even remember clearly now if I actually deleted anything of note that shouldn't have been on my computer. Some of the scans I ran yesterday didn't turn up anything, others did...so I'm sure I still have things of a malicious nature piggybacking on my computer.