Computers...

I knew I spoke too soon about the new PC. It's turning into an absolute nightmare. I can't connect to MSN Messanger which is very annoying and The Sims won't run at all now. It worked when I initially installed it, then I installed two expansion packs, the screen went mad and now it's defunct. I've uninstalled the whole lot and reinstalled the basic game but to no avail. Being a complete computer failure I have no idea what the problem is, however I have a feeling it may be something to do with the naff graphics/video card in this PC but I'm so clueless I don't know what a decent graphics/video card is.