> nothing shows up but the yellow boxes on the left with no writting in them.
If your video card has limited memory (or is using share system memory), I would suspect it's a big part of the problem. It happened to me quite often with my old comp and its original 32MB videocard. A more recent 128MB card reduced the issue's frequency, a 256MB card (and a new system) reduced it again.
However, for the other issues, hard to say… Are your video and sound drivers up to date? Maybe it's faulty hardware (say, video RAM), but if you don't play other games to compare, it's hard to say whether this is the issue.