Well, I have an offer, your choice to take it up though. Legacy of Kain speedrun games are generally new guy friendly, considering that I started with one and found it very easy to learn, nevertheless, what they have to offer:

1. You said you have a bad PC, Legacy of Kain games are 1995-2003. I do not think you'll have problems in terms of graphics or anything of the sort.

2.Most of the games are more reliant on glitches than RnG, but the glitches are very consistent once practiced enough and simple enough to learn.

3.Legacy of Kain speedruns are short enough, except for Blood Omen 2. Defiance is 20-30 mins, Soul Reaver 2 is 30-40 mins, The active category of SR1 which is allbosses are 1 hour and 10-20 mins.

4. They are pretty cheap. 7 euro per one of the games. Of course, if planning to buy 4 of the active ones then it'll be 28 euros.

So, if you are interested, I can give you my skype and introduce you to the other runners of the games and we can set you up with the routes and glitch guides of the games.