I'm guessing the PC-Phone issue is related to drivers. If you haven't already, you will need to download some drivers for your computer in order to access your phone as you would a portable hard drive.
Copied from a similar post:
"Click on this link and download the LG Mobile support tool for the PC:
Mobile Phone Support
When you have installed it, give it a run and on the right side of the window there should be a button that says "download USB drivers". When you click on it, the program downloads something like 4 driver files; not sure if they're all relevant, but might as well install them just to be safe.
Just be aware that the support tool program is a piece of junk (poorly translated and crashes every couple of minutes) but it will still do its job. You don't need to run it when you want to copy files, and I wouldn't even bother with the PCsync thing. Best way to transfer is to mount and use windows explorer for everything."
Regarding your download issue, if you don't have a file system browser in the phone already, you may be able to use the PC to browse the phone's SD card (considering the above remedy worked) and delete the file in the download folder if that's where it's trying to go.
If that doesn't work, the last resort would be to root your phone, and use rootexplorer to delete the download file in the internal storage (/data/cache or something like that). If it's a small file I wouldn't worry about it; if it's big, the Android system will delete it (by clearing the cache) when internal space runs thin anyway.
Hope that helps!
