Dell inspiron 1520 error code 2000-0146

I had the same problem and came across this solution that worked for me as well:
Re: windows Vista will not start 18 Aug 2009 07:28PM I was getting a the same error codes and couldn't get Windows to boot up at all. I went to BIOS set up (restart your computer and hit F12 when the BIOS screen comes up), went to onboard devices and changed the SATA Operations from ACHSI (don't know how it got there) to the factory default setting ATA. Then I started up in "repair mode" (which was an option that was coming up when I tried to boot up before but never worked) - it went through a repair check and went to login screen.
Prior to finding this - I tried several things including start up from the Reinstallation disc, but nothing worked. I was ready to buy a new hard drive, but don't have to. Works fine!
Not sure what caused the problem to start with. It is an "Inspiron 1520"

Yes, it is a hard drive issue and there is no fixing it temporarily without losing your data. The best thing to get your data is to get a USB enclosure for the type of drive it is (if it's a sata drive or a pata drive) or get an adapter that's an all in one (for 3.5, 2.5, and SATA). Then you hook your failing drive up to the converter, put it in the usb port of another computer and then it will show up as another drive that you can open and explore.