I'm new to Ubuntu/linux. Since my PC is very old and not very fast with Windows 7, I decided to give Ubuntu a try, so I downloaded and installed Ubuntu 11.10 today. When I first started it, I had bad 800x600 resolution and it was very slow and annoying. So I installed a driver for my graphic card and now everything looks very nice (1280x1024).But I think it's still far slower than Windows 7.

I tried to run in Ubuntu like a few people suggested on the forum but if I log in I get a black screen saying something like "this video mode cannot be displayed". I get that same screen when booting Ubuntu btw, but after about 15 seconds it disappears and just starts Ubuntu.

I also installed other drivers for my graphic card but everything stayed the same. I noticed that i.e. when I open Firefox or system settings it takes about 5 seconds till it opens (while Windows 7 takes under 1 second to start i.e. Chrome) and when I do this my CPU usage gets to 100% for a short time.

Computer specs:
Memory: 2GB RAM
Processor: Intel Pentium 4 2.8GHz
Graphics Card: Nvidia GeForce 6800 400MHz.

I read on various forums that 11.04 works flawless on many PCs, where 11.10 is very slow. Should I install 11.04 or could anybody help me with this problem?