Online content to LG PA70G

I'd like to have content from online and also my computer going to my LG PA70G. I tried coming out of the VGA computer port into the VGA port on the projector and was not pleased with the results. Image quality was lacking. Is there a better way to connect these units, or do I need to change resolution setting on the computer? Image was letter boxed more than screen on laptop, not very bright, and not sharp at all. The projector is ceiling mounted and would take 30' of cable for whatever connection I use so that cables will be hidden in walls and attic. Thinking of getting a Roku also. The size of the Roku is such that I could mount it up with the projector and use a very short HDMI cable and only need to run audio cable for the 30'. How have all of you found as the best way to input the signal? Can I attach a usb cable directly from a computer to the usb input on the projector and play content from the computer and online sources? Will that give a better result than the VGA input? Have had projectors for 20 plus years, but all were CRT's. Loving the size and performance of the PA70G; just want to get the best use of it possible. Not excited about a 30' HDMI cable though.

Thanks for the input. I'll try to adjust resolution on the computer, and try a different laptop as well. I don't have a clue what the image should/can look like when attached to a computer. I'm guessing it should be as good or better than the low def image I'm getting feeding it with a composite image from my lowly VCR. Should I expect the image to be about the same from a Roku type source as from a computer when playing internet content from each? The computers I have would need to use the VGA port, and something like a Roku I expect I'll be using an HDMI port. Sorry for all the elementary questions; but, I'm new to digital DLP PJ's

Last evening I used a different computer and adjusted the resolution to the pj's native. Looked good. watched some you tube and the HD clips were very nice. Today loaded some clips onto a flash drive and will try those tonight. I don't own any Blu-Ray movies. Only have some DVD's because those will play on my sailboat. Had to go that way after analog air broadcasts were eliminated. Too far from major market TV broadcasts to receive much on the boat. Thinking the Roku will serve better than a Blu-Ray player because I have space just above the computer for the Roku and not enough space for a Blu-Ray player (plus I'd need a step stool to access it). That would mean a short HDMI cable and a long audio cable (30'), cheaper by far and probably better quality signals too. I'm happy to be corrected though if you think I'm missing something. Is there something better than Roku out there? I don't want to be swapping cables up on the pj, so am I overlooking anything else? Thanks for you help.