Unable to install 12.04 from desktop cd n USB

[Navneet Kumar]

I have AMD athlon 64 1.8 ghz processor 2 gb ram Nvidia graphic card 256mb. I try to upgrade 10.04 lts to 12.04 lts but some dependency problem and unable to fix. I used desktop cd of 32 as well as 64 bit but it hangs at point when partition selection was done. Then I used usb disk same thing happen. Then 12.04 alternate usb disk I used but only base installation takes place and at point of select and install software from 18% to 85% jump and massage comes one step is not complete. After trying many times I choose installation of grub and try to install 12.04 files but in vain. Now all stalls here. I dont know commands of ubuntu only used graphic mode and used commands given on the internet for solving problem in the past.